AAIB investigation to Hawker Hunter T7 G-BXFI 22 August 2015

[falcon900]

Please be assured that I have no "agenda" regarding the takeoff or any other
part of the flight, beyond grasping for some rational explanation of what transpired. From the outset, Pilot error has been something of the bookies favourite, and the AAIB report more or less concludes the matter. There are however, at least in my mind, some loose ends.
I am happy to be guided by you Sika regarding how the Hunter should be handled, but if it was all so normal, why did the AAIB make the point that rotation was at a slower speed than "usual"?
Pulling up at a slower speed than usual into the "loop" plays a big part in this, and it does not seem without significance that some 25 minutes earlier, in his first interaction with airspeed during the flight, he dropped below his "usual" datum, and indeed towards the low end of (and arguably below) the viable range of speeds.
As I mentioned in an earlier post, figure 15 shows the rpm reducing materially during the climb phase of the "loop" and then increasing significantly after the apex. Why could this not indicate a mechanical issue followed by an attempted recovery? Pilot error seems rather a loose fit for the reduced rpm, and if I recall correctly, did the Hunter not have some form when it came to uncommanded transient thrust reduction?

[LOMCEVAK]

The report states that Rolls Royce were happy that there were no JPT or thrust anomalies on take-off for the accident sortie. There are clear statements of the JPT reading on take-off and during the accident manoeuvre, showing that the JPT on take-off was significantly greater than during the accident manoeuvre and within the normal range (580 - 690 C).

The Pilot's Notes state "Ideally, ease the nosewheel off the ground between 115 and 135 knots depending on configuration" and "Depending upon weight and attitude, the aircraft unsticks between130 knots and about 155 knots". On airtests, the take-off is performed initially with full back stick to check the minimum nosewheel lift-off speed; for this configuration it is usually about 105 KIAS.

Falcon900,

If the ground roll was greater than expected and the end of the runway was getting closer, even if below the normal nosewheel raise speed I think that some pilots may try to take-off at a slightly lower speed than normal.

[falcon900]

Thanks Lomcevak.
Whichever way you look at it though, the takeoff seems to have been harder work than you might have thought necessary.

Turning to the accident manoeuvre itself, I continue to be puzzled by the reduction in JPT and rpm after the pullup. it seems inconceivable that the pilot would have commanded a reduction on thrust during this phase, and in marked contrast to previous flights and best practice.
For me at least, the thought of an uncommanded reduction in thrust in the climb starts to put a different complexion on things...

[Tay Cough]

Whichever way you look at it though, the takeoff seems to have been harder work than you might have thought necessary.

You say you have no agenda.

The AAIB comment on the take-off but have no issues with it.

North Weald jet operators say a downwind take-off is not unusual.

An experienced Hunter pilot (sika humulta) says that the take-off was normal for a Hunter.

Which bit of the above is "harder work" exactly?

[PDR1]

Which bit of the above is "harder work" exactly?

Understanding why it is still being brought up? :ugh::ugh:

[falcon900]

In response to the question, the reference to harder work relates to Lomcevaks suggestion that everything was normal, but that the premature arrival of the end of the runway precipitated the lower than usual rotation speed.


I do not wish to flog a seemingly dead horse, and so am happy to move on from the takeoff, simply noting that nothing that has been said would contradict the possibility of the engine developing less thrust than the pilot was expecting for the given throttle setting. A question which is central to the accident sequence of events

[Nil further]

It isn't , because he missed all, his gates, had a track record of low flying and failed to abort when his manoeuvre went catastrophically wrong .

The un-proven (despite extensive investigation by some of the worlds best investigators and the engine manufacturers) issues with engine thrust are irrelevant and a monstrous red herring .

[PDR1]

...simply noting that nothing that has been said would contradict the possibility of the engine developing less thrust than the pilot was expecting for the given throttle setting. A question which is central to the accident sequence of events

Whilst this may be true, the whole POINT of having "energy check points" in an aerobatic display routine is to make it obvious to the pilot if something like a power reduction has occurred. I can remember Brian Lecomber saying (in his lectures on aerobatic display flying) that he would have a number of check points in a display, each explicitly chosen for a height or speed that would give an objective measure, and placed immediately before a manoeuver which could either be "ammended" (eg three flicks become two or one) or terminated altogether to suspend/abort the display.

The plain fact of the matter is that the aeroplane was both lower and slower than it should have been (both by massive margins) at what should have been an obvious energy check point. That the manoeuver or even the display was not aborted at that point is a matter of the pilot's responsibility - the cause of the energy loss is only a minor contributory factor. The pilot appears to have been drilling additional holes in the cheese. To suggest otherwise would be to suggest that a car crash was due to the light rain at a tight corner, rather than the driver's choice to enter that corner at 140mph.

[G0ULI]

Perhaps, just perhaps, the pilot was avoiding selecting absolute maximum power because of an awareness of the overspeed incidents with this engine? A bit like not mashing the throttle into the carpet in a classic car. You want to help maximise the life of components and keep the vehicle running.

[PDR1]

That may be true, but that would just make it even MORE important that he should check the speed/height achieved at the top of the manoeuver, surely?

[Quietplease]

I have to hand Pilot's Notes for the Hunter F4. There are probably considerable differences from the T7 but still probably quite relevant.
The very short section (87) on aerobatics reads:-
(a) Until experience is gained, the following speeds, in knots, are recommended:-
Roll 350 Loop 425 Roll Off 450 Vertical Roll 500.
(b) It is recommended that until experience is gained, loops are started in the height band 10,000ft to 15,000ft.
No , I have not inadvertently added a zero to the last two figures.
I'm not sure I would consider myself experienced on type with 43 hours over 4 years.
11 practices in 4 years is not experienced. I would do at least that many in a month and after 3 seasons displaying JP3 and JP4 still worked to a 500ft base and I still very nearly killed myself once. I did watch an experienced but under-practiced colleague do a Shoreham except he impacted in an empty field. I can recall the whole scene in slow motion. We nearly dropped the coffin there was such a weight of sand in it.

With his experience, I find it surprising that the pilot was happy to display at a small airfield surrounded by housing. Even more surprising, and much more worrying, that anyone would authorise such a display. It seems pure luck that the death toll was not massively greater.
Please can we forget all the irrelevant stuff about the takeoff, altimeter settings, blah blah blah. A pilot, inexperienced on type, lacking in practice, may well have made an error in a display which should not have been happening.

[langleybaston]

.............. surrounded by housing .......?

Not relevant really, and most certainly not true.

[falcon900]

Gentlemen,
I think we are in truth agreeing about most things here, and to be clear, I am not trying to exculpate the pilot or anyone else, just trying to string together, if only in my own mind, a coherent and credible sequence of events.
My current hypothesis goes along the following lines;
He sets the throttle levers for the start of the "bent loop", and accelerates towards the first gate, anticipating achieving the target entry speed as he has before.
He misses it, interestingly by roughly the same % margin as missed his target rotation speed on takeoff....
He begins the climbing phase of the "loop", and either a) he selects a materially REDUCED level of thrust or b) there is an uncommanded reduction of thrust.
He doesnt "feel" the reduced thrust, and arrives at the apex of the loop.
Glances at altimeter, and with pointer covering the numbers, reads it as 3700 rather than 2700.
Feels aircraft close to stall, but believes himself to have sufficient height to complete the manoeuvre, and applies power to address airspeed.
The rest, sadly, we know for sure.


I am not suggesting that this doesnt amount to pilot error, but at least to me, if the reduction in thrust was uncommanded , it all seems more understandable, if no less tragic.
The alternative would seem to require that we accept that the power was intentionally reduced during the climb.

[sika hulmuta]

Falcon900, we are singing from the same hymn sheet. That the accident happened because of pilot error is not in dispute. But why?

To my mind, there was little wrong for the first part of the flight, Knowing the aircraft and runway I can even rationalise the downwind take off which no pilot would countenance lightly. Yes, we can say this happened 2 kts early or late, but that really is Monday Morning quarterbacking. I can easily and do make such errors every flight, every day. It falls within what I call " normal".

However from just before the pull up there are suddenly gaping discrepances, from a previously "normal" flight, and I agree with others that the report seems to be thin on the human factors and medical side. It certainly stands greater scrutiny.

My agenda is to understand what actually happened to try to prevent it happening again. The Why.

Saying "It was pilot error" is stating the obvious and achieves little more than pointing a the finger of blame, which may be sufficient for those who lost loved ones, but not for me. Especially if the blame is subsequently mitigated by circumstances found to be outside the control of the pilot.

Something happens just prior to pull up which is not explained. The pattern of control and flight suddenly changes from "normal" to abnormal. Why?

[deadheader]

The report is very exhaustive and does offer an answer to the 'why', albeit not to the satisfaction of most armchair investigators' curiosity: 'We can't know with a high degree of certainty'.

Through comprehensive examination of all the available evidence, several plausible contributing factors have been determined and explored in detail, leading to several safety recommendations in an effort to learn from the errors made and prevent reccurance, but there is no smoking gun and nor are we likely to ever find one.

IMHO

[Onceapilot]

May I invite anyone interested to view this clip at the 04 seconds after the start point?
https://www.youtube.com/watch?v=Mr4POEBz81s)

The heavy trail is backlit and seems to come from the Fuselage. I do not believe this trail is commented upon in the report, only another that is described as "from the wing tank area", or words to that effect.

[deadheader]

At 04 seconds it passes directly between the sun and the camera; the exhaust is highlighted as a result. Just my two penn'orth...

[Tay Cough]

...precipitated the lower than usual rotation speed.

For Pete's sake. It's on the previous page. That is the normal Hunter technique.

[falcon900]

Taycough, it is the AAIB who are saying it wasnt his usual rotation speed.

[n305fa]

At 04 seconds it passes directly between the sun and the camera; the exhaust is highlighted as a result. Just my two penn'orth...

I totally agree, having played with hunters there's no fuel or fluid drain in the lower rear fuselage(aft of the transport joint). There's nothing in that area that would give you a plume, and it doesn't show up on other images.

Regarding the AAIB not reporting on things we think significant, I will paraphrase a qote from a retired AAIB inspector who was presenting at a course I was on. "AAIB reports report the findings and analysis relating to an accident or incident, they do not provide a comprehensive description of every line of enquiry That was considered and dismissed during the course of the investigation". I imagine if they did that this report would be considerably larger.

[Tay Cough]

Taycough, it is the AAIB who are saying it wasnt his usual rotation speed.

From the comments on this thread by Hunter pilots, the AAIB may be mistaken.

[Onceapilot]

Quote:
Originally Posted by deadheader View Post
At 04 seconds it passes directly between the sun and the camera; the exhaust is highlighted as a result. Just my two penn'orth...
I totally agree, having played with hunters there's no fuel or fluid drain in the lower rear fuselage(aft of the transport joint). There's nothing in that area that would give you a plume, and it doesn't show up on other images.

Regarding the AAIB not reporting on things we think significant, I will paraphrase a qote from a retired AAIB inspector who was presenting at a course I was on. "AAIB reports report the findings and analysis relating to an accident or incident, they do not provide a comprehensive description of every line of enquiry That was considered and dismissed during the course of the investigation". I imagine if they did that this report would be considerably larger.

Great! As it happens , I don't agree with either of you.:) What I see is a considerable liquid trail from the fuselage that occurs seconds before the accident, is clearly shown in that clip and, is not commented upon by the report. I cannot understand that omission.

[Lemain]

I agree with your interpretation however cameras DO lie (lens aberrations, reflected light etc.) When you slow that image right down in a movie clip editor it looks as though only some kind of vapour or liquid trail could have caused it. As you say, the odd thing is it's not detailed in the report. Since we could never determine that, the next question is "If it is fuel/vapour then where might it have come from?" And the next question is "How might that have affected the performance or the pilot?"

[Tailspin Turtle]

Back to the beginning of the accident maneuver: there was an additional gate besides the speed (very important) and altitude (in my opinion, not so important because one should fly a loop so as to be able to come out of it above the starting altitude; you then finesse the pull out to come down to the height above ground desired at its completion), That third gate is the point at which to begin the bent loop so as to come out on a line parallel to the show line. He may have begun the pull up late since it appears that he wasn't far enough west as he was coming down its back side. If on the run-in, he realized that he was past the point where he should have started up, he may have glanced at the airspeed indicator and decided, as hard as it is to believe, that he was going fast enough to begin the maneuver.

[H Peacock]

To be perfectly honest, I don't really get this 'bent' loop business. If you're after a small change in heading (he was) why not just make a very minor correction going over the top or even 3rd quarter to roll out pointing along the required datum. If you need a bigger change of heading, surely you put the roll in the upward vertical. Any errors in your roll will not make any change to the height that you then peak at, in addition, the fractional pause in your pull-up means you'll easily achieve you're apex gate height/speed. If you roll too early during the 1st quarter you're almost into barrel roll territory but with not enough height to half-loop out of.

[DaveReidUK]

Bending a loop at the apex will result in a different track over the ground compared to bending it (by the same amount) in the vertical.

[Onceapilot]

Quote Lemain:

I agree with your interpretation however cameras DO lie (lens aberrations, reflected light etc.) When you slow that image right down in a movie clip editor it looks as though only some kind of vapour or liquid trail could have caused it. As you say, the odd thing is it's not detailed in the report. Since we could never determine that, the next question is "If it is fuel/vapour then where might it have come from?" And the next question is "How might that have affected the performance or the pilot?"

My real point here is that the report fails to identify this important and unusual evidence.
Here is the link again, the trail is visible at around 04 seconds after the start.

https://www.youtube.com/watch?v=Mr4POEBz81s)

[bront]

What about the possibility of the ASI reading incorrectly i.e. over reading?


The result would be rotation too early and entry to manoeuvre too slow.


Falcon 900 mentioned 'He misses it, interestingly by roughly the same % margin as missed his target rotation speed on takeoff....'

[Lemain]

Quote Lemain:



My real point here is that the report fails to identify this important and unusual evidence.
Here is the link again, the trail is visible at around 04 seconds after the start.
Yes, I agree. I loaded the vid into one of my video editors and looked at it frame by frame. It doesn't look like a light aberration to me. However the res isn't as good as one would like. It looks like a condensation trail. An experienced Hunter pilot on this thread said it's unlikely - obviously he has detailed knowledge of the airframe and engine. If a con-trail, what is condensing? Unburnt fuel? Water? Smoke (i.e. a mix of combustion products)?

[Blacksheep]

You want to help maximise the life of components and keep the vehicle running.If that was what he was trying to do he failed to achieve his aim, big-time. The AAIB investigation was as objective and professional as always and their conclusions are clear and evidence based.

[dynamics]

Given the historic facts and evidence, perhaps the direct way to prevent this particular tragedy happening again is to ban high-speed, low-level split-s/vertical loop maneuvers. The common denominator in all such accidents. I for one would favor this over further type or location restrictions.

In addition to the Thunderbird crash and Typhoon near miss posted above, here are two more unfortunate examples that spring to mind where neither the pilot's experience nor platform's capabilities were in-doubt.

Hawk, 1999
https://www.youtube.com/watch?v=nBF52ai6ivc (https://youtu.be/nBF52ai6ivc?t=237)

Blue Angels, 2016
https://www.youtube.com/watch?v=N4WKX1yVHhQ

Time and time again we witness the lethality of such an unforgiving maneuver. Perhaps we humans need to concede that it's just a little beyond us and that it's just not worth it, anymore... :(

[sycamore]

OAP/Lemain; cooling air outlet from the conditioner pack as it was a hot day,or further back is an access panel to the rear tank contents switchery...?

[Onceapilot]

Sycamore: I do not know what that trail is but, it seems to have been missed in the report. Strange that the other far less significant "mist" from the wing tank area merited coverage! I suspect that this fuselage trail was overlooked!:uhoh:

[Tailspin Turtle]

To be perfectly honest, I don't really get this 'bent' loop business. If you're after a small change in heading (he was) why not just make a very minor correction going over the top or even 3rd quarter to roll out pointing along the required datum. If you need a bigger change of heading, surely you put the roll in the upward vertical. Any errors in your roll will not make any change to the height that you then peak at, in addition, the fractional pause in your pull-up means you'll easily achieve you're apex gate height/speed. If you roll too early during the 1st quarter you're almost into barrel roll territory but with not enough height to half-loop out of.
It took me a couple of viewings of the video when it was first available to figure out what the maneuver was and moreover, what its purpose was. One shortcoming is that you roll away from the venue and put it behind you as a reference point for lineup, potentially delaying your increase in pull on the back side momentarily while you looked for it. If I was to bend a loop with a roll, I would prefer to do it on the back side so that the show-line runway was always in sight. However, if a low pass down the show line was to be made coming out of the loop, that would require displacing the initial run-in farther to the east, adding time between the opening pass and the next maneuver. It was also informative to see all the restrictions to altitudes and overflights on the map in the AAIB report, which may have dictated the bent loop as flown.

[RAT 5]

If I was to bend a loop with a roll, I would prefer to do it on the back side so that the show-line runway was always in sight.

Indeed. All aeros I've been trained in, or seen demo'd, the loop is simple and any line correction is made after the apex on the way down. If the climbing loop is combined with rolling it is a proper quarter roll, or more usually a half roll, even full roll to a predetermined datum then pull through. A line adjustment on the climb seems a guess at best.
Many questions, so few answers.

[Chronus]

Another hypothesis for the roll could be that he did realise he was too slow and low and twitched the stick for an escape with a slight roll which bled off more of the precious little energy left, then thought he would have a better chance on the descent. Having got over the top and nosed it into the descent, eye balling the proximity of the ground, realised he had little height to spare and the only way to turn the betting odds in his favour might be by going straight down for the deck.
All that RAT 5 suggests is true, but only so if sufficient height and energy remains in hand. In this case neither were present.
David Learmount has published opinion on his web site. Here is the link:
https://davidlearmount.com/tag/bent-loop/
I tend to agree with him on all his comments. Makes a lot of sense. Especially those about faulty components.

[H Peacock]

In addition to the Thunderbird crash and Typhoon near miss posted above, here are two more unfortunate examples that spring to mind where neither the pilot's experience nor platform's capabilities were in-doubt.

Dynamics, I didn't know GW who was displaying the Hawk 200, but I suspect his lack of relevant experience (LL display flying) was the main cause of the 1999 accident.

[McDuff]

HP, GW was Graham Wardell, a former test pilot (and the first foreigner to fly the F117) who had, we have to assume, had a proper workup in the Hawk for the display. It would have been in BAe's interests to assure the proficiency of its display pilot for an aircraft that it was trying to sell. When I spoke to fellow Flt Ops individuals, there was no hint that Graham was anything other than proficient.

[Hebog]

an anyone tell me what the red flash is on the top of the aircraft is in this clip at 2:28.


https://www.youtube.com/watch?v=JnczDEiFFN4

[LOMCEVAK]

McDuff,

Graham Wardell was the first RAF pilot on an exchange tour on the F-117 but he was not the first foreign/British pilot to fly it (2 had flown it in 1986)

H Peacock,

For a given pitch rate in the upward half of a loop, any roll introduced before the vertical up line will reduce the apex height (just geometry). The correct technique, as you have said, is to reduce the pitch rate whilst rolling (or even to maintain a pure up vertical line) and then the apex height will be the same or greater. However, in the Shoreham accident it appears that maximum instantaneous pitch rate was maintained throughout the upward half, including during the roll. Appendix H of the report covers this.

[LOMCEVAK]

Hebog,

It is the anti-collision light, a red rotating beacon (standard fit on a T7).

[Hebog]

Thank you Lomcevak - couldn't see it on anything else on the video.


If his G indicator wasn't working correctly, could he have exceeded the aircraft limits without knowing it causing damage either internally or external. As it would appear that the fatigue meter was only checked once a year and not after each flight, as per the AAN. And with the extensive damage to the aircraft some damage may not have been obvious to the AAIB, like the pitot which they stated couldn't be checked for serviceability.

[G0ULI]

The display manoeuvres were calculated to be in the region of 3G and well within the capabilities of the aircraft. The non functioning G meter should have read up to 9G, so while damage might occur below this figure, the manufacturers clearly thought that the airframe would survive this amount of force and be capable of landing safely for repairs. I seriously doubt that any pilot would want to pull more than around 5G in what is essentially fun flying for the purposes of entertainment.

[kenparry]

If his G indicator wasn't working correctly, could he have exceeded the aircraft limits without knowing it causing damage either internally or external.

Not at the quoted range of IAS. The limit is 7g, and you need around 420kt IAS to achieve that. The Hunter is a tough bird - there have been intances of 9G+ without damage.

[Lemain]

The Hunter is a tough bird

Is or was? From the AAIB report maintenance was maybe(?) not up to the standard as when she was in service. Not trying to point blame just considering that caveat.

[Hebog]

He was certainly going some on the dashcam clip on you tube. Maybe as a result of the increased RPM that is detailed in the report, which was not usual compared to other video clips of previous flights by the pilot.


Thought that aeros would generate more than 3G, and an earlier display was 5.5G and we have no idea if the aircraft had exceeded limits prior to Shoreham, causing an issue that went undetected. As there is no data on the fatigue meter readings taken at the last annual inspection and during the investigation.


Another AAIB report G-HHUN makes interesting reading with regard to engine surges and stagnation that can occur. Could this explain the unusual behaviour of the RPM detailed in the report for BXFI.

[PDR1]

The conclusion with G-HHUN was that the engine was destroyed by the inadvertant operation of the HP fuel pump isolation switch (when the pilot was reaching for the "smoke on" switch). It's burned into my memory because I was at DUnsfold on the day, helping with preparations for the the next day's Families Day. Whilst the report includes some commentary about potential issues with the bleed valve control unit I'm fairly sure I remember the conclusion was that this would have no discernible effect on the power delivery unless it progressed to a full surge (compressor stall).

There was nothing to indicate a surge or similar event in the case of the SHoreham aircraft was there?

[Lemain]

From the report, the only instance I can find of the word 'surge' is in para 1.6.9

This restricted the fuel flow to the fuel nozzles when the gun was fired,
to prevent compressor surges. This system was deactivated when the cannon
was removed from the aircraft during its military service.

So the system was "deactivated" rather than removed?

[H Peacock]

Lemain. The Hunter had the 'Gun Dip' system fitted to alleviate the engine surge problems associated with the disrupted air intake flow during gun firing. This system has indeed been deactivated on all of the civilian Hunters.

The Hunter also had a means to isolate the twin HP fuel pumps to maintain a fuel flow in the event of HP pump failure. This was activated by a guarded switch in the cockpit behind the throttle. This High Pressure Pump Isolation Switch (HPPIS) could result in a considerable over-fuelling of the engine, the consequences of which would be an almost instant over temp/destruction of the turbine. It was concluded that the engine failure of G-HHUN was caused by the pilot inadvertently opperating the HPPIS when trying to activate the aircraft's smoke system.

It was yet another Hunter crash which killed it's very, very inexperienced Hunter pilot.

[PDR1]

From the report, the only instance I can find of the word 'surge' is in para 1.6.9


I just looked up the bulletin (https://assets.digital.cabinet-office.gov.uk/media/5422f5f0ed915d1374000589/dft_avsafety_pdf_502233.pdf) which discusses surge in three contexts - the Gundip system, the BVCU and the chance of stagnation/surge if the engine was mishandled at low speed and high AoA. But none of these make it into the recommendations because they seem reasonably satisfied that the engine was destroyed through HP fuel pump isolation without closing the throttle.


So the system was "deactivated" rather than removed?

According to the above bulletin the Gundip system was disabled under mod KT.1321, but the implementation only disconnected the airframe side of the system. This sort approach was quite common because it negated the need to re-analyse the weight&balance calcs for the ODM and rebalance electrical and cooling systems (complicating the mod and massively increasing the cost). The bulletin also suggests that after an aeroplane was lost due to suspected electriocal noise pick-up in the retained wiring a further mod removed all the wiring, but this was after the aeroplane had been sold on so it wasn't an incorporated mod.

But again, nothing in the Shorham report that I've seen would point towards problems related to the gundip wiring as a potential cause.

[bvcu]

BVCU and system can cause lack of power as i've already posted .You can have correct rpm and jpt but low thrust if bleeds open. I suspect it was discounted as the power was adequate for takeoff which i would have thought proved things with a relatively short runway , tailwind and warm day.

[kenparry]

The Hunter also had a means to isolate the twin HP fuel pumps to maintain a fuel flow in the event of HP pump failure. This was activated by a guarded switch in the cockpit behind the throttle. This High Pressure Pump Isolation Switch (HPPIS) could result in a considerable over-fuelling of the engine, the consequences of which would be an almost instant over temp/destruction of the turbine.

In the interests of accuracy, this system was fitted to the 100-series Avon (and thus relevant to G-HHUN and the Shoreham T7) but was not on the 200-series as used on the F6 and its derivatives.

[Lemain]

BVCU and system can cause lack of power as i've already posted .You can have correct rpm and jpt but low thrust if bleeds open. I suspect it was discounted as the power was adequate for takeoff which i would have thought proved things with a relatively short runway , tailwind and warm day.

While that might be evidence that it was functioning correctly at takeoff, might it have failed in some way during the manoeuvre? If so, is it likely there would have been evidence from the wreckage? Might a failure have conceivably been a contributory factor? I'm wondering if something distracted the pilot?

[n305fa]

BVCU and system can cause lack of power as i've already posted .You can have correct rpm and jpt but low thrust if bleeds open. I suspect it was discounted as the power was adequate for takeoff which i would have thought proved things with a relatively short runway , tailwind and warm day.

Re the above, if the bleed valves are open, that will produce a higher JPT for a given rpm. Thrust (mass flow rate) is directly related to the compressor delivery pressure and the fuel flow (given fixed compressor and turbine geometry). Open compressor bleeds reduce the compressor delivery pressure (CDP) for any given selected throttle position, this results in the accel control unit scheduling an increase in fuel flow, through the servo fuel system to produce a CDP increase to restore the mass flow rate. An engine producing a given thrust with bleeds open will have a higher rpm and jet than the same engine at the same thrust with the bleeds closed. I've seen this on testbeds on the Avon & Spey, and a number of other engines

[bvcu]

on the aircraft the marginally higher JPT on a 100 series was not visible on this type of gauge. In this day and age you would probably see it on a digital gauge but not on those. This was the reason we were doing daily engine runs to check bleed valve settings in the early eighties when there was an issue with the BVCU diagphram material until they were modified. That was checked on strip according to the report so can't see it would have been the problem. We have come a long way in terms of engine instrumentation nowadays ! If there had been a noticeable lack of thrust the RPM would have been continuously at the top end of the scale to achieve enough thrust you would think , so the thrust reduction doesn't make sense unless there was a transient high RPM/JPT fault which caused him to momentarily throttle back ? We'll never know.

[Lemain]

so the thrust reduction doesn't make sense unless there was a transient high RPM/JPT fault which caused him to momentarily throttle back ? We'll never know.

I'm concerned why the AAIB report didn't cover that possibility?

[LOMCEVAK]

There is data in the report regarding RPM, albeit from an analysis of the action camera audio, and JPT as viewed on the cockpit video data. The relationship between the two was consistent and, therefore, there appears to be nothing to suggest a bleed valve problem. This is probably why it was not analysed or investigated further. With a 100 series Avon the normal manifestation to the pilot of a bleed valve malfunction is a low JPT for a given RPM when at a high value. The pilot does not have a thrust meter and any differences in acceleration due to a variation in thrust are subtle and may not be noticed other than by an acceleration check on take-off. The only guaranteed indication to the pilot of an Avon 122 with a bleed valve stuck open is a JPT of less than 560 C at maximum RPM.

For those who seem to be intent upon trying to identify an engine malfunction I would like you to consider the fact that the aircraft reached the apex with sufficient airspeed to enable an escape manoeuvre to be flown safely even with idle thrust which is not significantly greater than the zero thrust from a flamed-out engine. And it would be an uncanny co-incidence for an engine malfunction that caused a significant reduction in thrust to occur during a manoeuvre which the pilot entered at an airspeed less than the minimum planned and during which he also failed to perform an escape manoeuvre despite being significantly below the gate height.

[airpolice]

For that number of holes to line up, there would need to be no cheese at all.

[DaveReidUK]

And it would be an uncanny co-incidence for an engine malfunction that caused a significant reduction in thrust to occur during a manoeuvre which the pilot entered at an airspeed less than the minimum planned and during which he also failed to perform an escape manoeuvre despite being significantly below the gate height.

Can you explain your logic ?

The less-than-full-thrust, low entry speed, low apex height and failure to perform an escape manoeuvre that you cite are all AFAIK undisputed facts.

So why does attributing the reduced thrust to an engine malfunction turn this into an "uncanny coincidence" ?

[LOMCEVAK]

DaveReidUK,

In hindsight I should have said 'very unfortunate co-incidence' rather than 'uncanny'. The reduced RPM and JPT are due either to a pilot selection or an engine malfunction. An engine malfunction is a relatively low probability event and so it would be very unfortunate if it coincided with a manoeuvre when the required parameters were not achieved and the correct course of action was not followed.

[falcon900]

Lomcevak,
Most accidents of this nature are traced back to a series of unfortunate coincidences; the holes in the cheese.
The point you make is the right one though, and one I made earlier. Everyone seems to agree that rpm and hence thrust were reduced during the climb: either the pilot commanded it, or he didnt.
For my part, it seems inconceivable that he would have commanded it, hence I am thinking about whether it was another in a string of instances of an Avon 122 uncommanded thrust reduction.

[Onceapilot]

Unfortunately, the 100 series Avon has a history of power output incidents that Rolls-Royce were unable to fully explain, even when they were fully responsible for the engine in Service use. The AAIB report quotes this fact. Additionally, the Avon fuel control system includes several subsystems, other than the bleed-air system, that interact and effect engine performance. I suspect that no-one today can prove exactly if that engine was performing correctly on the day of the accident, apart from the stated parameters in the report. However, there does appear to be some conjecture bias against the pilots actions, rather than the machine.
As always, I try to limit my comments to facts.

[DaveReidUK]

Everyone seems to agree that rpm and hence thrust were reduced during the climb: either the pilot commanded it, or he didn't.

For my part, it seems inconceivable that he would have commanded it, hence I am thinking about whether it was another in a string of instances of an Avon 122 uncommanded thrust reduction.

The AAIB, on the other hand, have not ruled out either possibility:

"It was not possible to determine if thrust was modulated by the pilot during the climb because the throttle was not visible in the cockpit image recording during this part of the accident manoeuvre. However, of the two loops recorded during previous displays, where the cockpit action camera captured throttle position, one showed variation of the throttle position during the upward part of the vertical manoeuvre. In that case movement of the throttle correlated with engine speed changes. Throttle position changes can only be made by the pilot, indicating that he had deviated from his stated throttle technique on that occasion. Therefore, whilst mechanical issues cannot be ruled out, it is possible that the variation in thrust during the accident manoeuvre was commanded by the pilot."

[H Peacock]

If you're flying a relatively small flying machine with just the one engine then you'll definitely be aware of any noteable thrust and/or rpm variations without having to look at any gauges; even more so if you've not physically commanded them by moving the throttle!

That said, even in the event of a total loss of thrust at any stage of the display sequence, if the correct/appropriate actions were taken then no one would have died.

[DaveReidUK]

Looks like it's time for a reminder that the complete report is available to download (and read) from the AAIB website:

https://assets.publishing.service.gov.uk/media/58b9247740f0b67ec80000fc/AAR_1-2017_G-BXFI.pdf

"The [test pilot] explained the difficulty in detecting reduced thrust during the ‘up vertical’ part of the manoeuvre, and given the pilot’s focus on external cues, if it was not selected by him he was probably unaware of it."

[Chronus]

The manoeuvre was entered at 310 kts instead of 350 kts. What would the g forces be at the pull up at both speeds. Would it be an expectation of a pilot of the required level of experience, skill and training to recognise and guard against both extremities; excessive or insufficient energy. This particular aircraft, built for the job as a gun platform had plenty against excess, more than 9 g. So that did not present a problem. But why not accept this generosity where and when it was necessary.

[DODGYOLDFART]

If you're flying a relatively small flying machine with just the one engine then you'll definitely be aware of any noteable thrust and/or rpm variations without having to look at any gauges; even more so if you've not physically commanded them by moving the throttle!

That said, even in the event of a total loss of thrust at any stage of the display sequence, if the correct/appropriate actions were taken then no one would have died.

I could not agree more HP. Ultimately IMHO this tragedy has to come down to either pilot error or pilot incapacity of the mental of physical kind. However proving either would now seem to be impossible so we are left with nothing more than pure conjecture.

[cessnapete]

HPeacock

That said, even in the event of a total loss of thrust at any stage of the display sequence, if the correct/appropriate actions were taken then no one would have died.[/QUOTE]

Ridiculous conclusion, if for example there been a total loss of thrust there would have been no control over where and perhaps on whom the aircraft impacted.

[H Peacock]

Ridiculous conclusion, if for example there been a total loss of thrust there would have been no control over where and perhaps on whom the aircraft impacted.

Sorry Cessnapete, but a fast jet in flight will have plenty of kinetic energy. Provided you can still steer the thing after a total loss of thrust, then you can invariably park it in an open space.

Do you think they'd allow a single engine Hawk through the middle of the TVAA (London) at 1300ft if there was 'no control over where and perhaps on whom the aircraft impacted'?

We'll have to agree to disagree!

[DaveReidUK]

Ridiculous conclusion, if for example there been a total loss of thrust there would have been no control over where and perhaps on whom the aircraft impacted.

Why don't you guys get together and rewrite the AAIB report with your own conclusions? :O

In the meantime, for the rest of us, there's an extensive discussion in the report on the pilot's options following a partial or complete loss of thrust at various stages of the manoeuvre - none of them involving loss of control.

I'll leave finding it to the interested reader, of whom there seem to be disappointingly few on here ...

[falcon900]

Hopefully you might allow me to join you in your interested reader camp Dave, if only to stop you becoming lonely!
For my part, I am not trying to rewrite or dispute the AAIB report, but simply trying to come up with some sort of rational explanation for what transpired, not because I think it will exculpate the pilot, but because I think it might serve to put his actions into their proper context.
It seems to me that there is a world of difference between someone recklessly flying around wilfully disregarding normal safety protocols, and someone who fails to spot an uncommanded reduction of thrust in time to avail themselves of a 4 second long opportunity to escape safely.
Whilst I am not at the latter end of that spectrum just yet, the more I read, and the more this discussion goes on, the closer I am edging towards it.
Why does it matter? Well, because if it was in truth a technical issue which put the pilot unknowingly into the fateful position, and under pressure he made the wrong call without fully appreciating what had happened, it is hardly a unique scenario. Like everyone else, Pilots are not infallible, and under duress can get it wrong and it is reasonably foreseeable that they might. The tragedy which unfolded has as much to do with the decision to have a display of that type in that place, as it does with what did or didn't happen during the fateful 4 seconds.
In fairness, the AAIB report acknowledges this; it is just the subsequent flow of debate which doesn't seem to. In other words, it is important to understand the context of the pilots actions to set them properly in the overall context.

[Lemain]

falcon900 -- Excellent post and agree. There are several reasons to continue picking over the bones.

a) The relatives deserve an explanation, for closure
b) There will be insurances in place. While money cannot restore the human loss it could help the relatives of the innocent.
c) If there are safety issues (human and mechanical) that can be addressed it might prevent future tragedies
d) The pilot will have to live with this for the rest of his life - and so will his family. Likewise all those responsible for the display and the airworthiness of the a/c

[LOMCEVAK]

In the report, Appendix H, para 15.c.(3) states: "These tests indicated that the height loss from apex during the accident manoeuvre was not affected significantly by power setting". Therefore, whatever the thrust was past the apex the outcome of the pull through would not have been significantly affected. Similarly, the thrust at the apex would not have affected the pilot's ability to perform an escape manoeuvre. However, the low thrust on the pull up was significant in that it was a contributory factor to the low apex height and low apex airspeed achieved.

[H Peacock]

In the meantime, for the rest of us, there's an extensive discussion in the report on the pilot's options following a partial or complete loss of thrust at various stages of the manoeuvre - none of them involving loss of control.

Why does it matter? Well, because if it was in truth a technical issue which put the pilot unknowingly into the fateful position, and under pressure he made the wrong call without fully appreciating what had happened, it is hardly a unique scenario. Like everyone else, Pilots are not infallible, and under duress can get it wrong and it is reasonably foreseeable that they might. The tragedy which unfolded has as much to do with the decision to have a display of that type in that place, as it does with what did or didn't happen during the fateful 4 seconds.

Guys, I accept there was less thrust than required during the first half of the loop - be that an engine abnormality or pilot action. However, apart from the secondary consideration of line feature/rollout track and perhaps the required exit speed, the primary concern before reaching the apex is gate parameters. The whole reason behind having a gate is to stop you trying to finish the loop without enough sky below you. As mentioned before, the apex gate is not a snapshot, you can clearly see it coming well before the apex if you are 1000ft low. To continue after being say 100ft low is naughty, and going to be a late call, but you miss it by 1000ft! Furthermore, 4 sec is ample time to recognise any gate error and then stop the loop. You are already expecting to make the appropriate decision. Again, mentioned in detail before, unload and roll out. If too slow, keep a bit of pull on, nose below horizon, IAS rapidly building, unload then rollout.

If we are going to conclude that 4sec might not be enough time to assess, and then action a recovery then that will be the end of any looping at air shows. AH wasn't the first and won't be the last - but he crashed because he continued his loop despite having failed to achieve his gate. Had he not failed to achieve his gate the accident would not have occurred, but as to why he failed to achieve it, that's simply an observation.

Gate parameters - it's really that simple!

[hum]

Interesting pic from another forum showing actual vs 'planned' (according to AAIB video) pull up..

http://i50.photobucket.com/albums/f318/gerryhum/image_zpsi9jy48x5.jpeg (http://s50.photobucket.com/user/gerryhum/media/image_zpsi9jy48x5.jpeg.html)

A very early pull, inapropriate throttle and aileron inputs, no escape attempt until a late pull very strongly suggest a transient cognitive impairment..

[falcon900]

H P,
Agree entirely about gates, and indeed to a degree about 4 secs being enough time to check at the apex.
However, the second hole in the cheese in my hypothesis is that not having sensed the loss of thrust, he glanced at the altimeter at the apex, and took the partially obscured figure to be 3700, more or less what he might have expected, rather than the actual and problematic 2700. I don't think his 4 seconds was used searching for solutions, as I suspect he didnt' realise he had a problem.
Absolute conjecture, I admit, but would explain the continuation of the manoeuvre, with no apparent attempt to escape from it.

[LOMCEVAK]

One aspect to consider regarding the obscuration of altimeter digits by the needle is that the needle is only stationary at the instant at which the aircraft is at the apex. The rate of needle movement is low near the apex but needs to be considered with respect to the arc of movement over which any potential confusion between the 2 and 3 in the 'thousands' digit position exists.

[H Peacock]

One aspect to consider regarding the obscuration of altimeter digits by the needle is that the needle is only stationary at the instant at which the aircraft is at the apex. The rate of needle movement is low near the apex but needs to be considered with respect to the arc of movement over which any potential confusion between the 2 and 3 in the 'thousands' digit position exists.

Not quite Lomcevak, there will always be a finite lag in a dynamic manoeuvre such as a loop. Moreover, he probably had it in Sby so there would have been an even more noticeable lag, ie, alt still slowly increasing as his RoC hits zero. Partly why you take a couple of peeps of the alt during the 2nd quarter of the loop; 'how's it looking!'. Taking a single snapshot of the alt at apex and then making a call is not the way to do it. It's a little like an approach DH. You don't hit it then make the call unprepared, but you need to be ready for the GA so you can have auctioned it at DH. He doesn't need to initiate his flyaway at the apex, but he must have made the 'yes/no' call. If you are guilty of trying to just take a snapshot without any prior awareness of 'how's it going?' Then there's a good chance you'll get it wrong!

[LOMCEVAK]

HP,

Agreed that there will be a lag but that is, by definition, a phase difference so the needle will still be moving; it is just that the reversal in needle direction will be slightly after the actual apex. Actually, the greater problem in standby is that the needle sticks and then jumps. Therefore, as you say, the need is to introduce the altimeter into a scan pattern prior to the apex rather than just take a snapshot.

[Whipstall]

A very early pull, inapropriate throttle and aileron inputs, no escape attempt until a late pull very strongly suggest a transient cognitive impairment..


Or inadequate currency...

[Treble one]

I have no wish to see the pilot un-necessarily denigrated or picked over in public, but I have to say that there is absolutely no evidence of cognitive impairment or incapacity to be a contributory factor in this accident.


This is almost getting silly to be honest. Just because an experienced pilot appears to have made a catalogue of uncharacteristic errors during a flying display, which you maybe wouldn't expect, then everyone rushes to say that he was impaired or incapacitated.


Maybe he had a bad day? Maybe he was complacent? Maybe he was ill prepared? Maybe he made a series of errors of judgement?


Could that not be it?

[mrangryofwarlingham]

Hum

You're probably right.
In my view the rather extraordinary combo of TIA, uncommanded reduction in power, too little margin for error.
The few hours on type didn't help. Although he had been to Bruntingthorpe 2 weeks beforehand.

HP
If you go in slow and low I agree a scan pattern inside becomes more important.
No one that I know off considers a loop to start when 30 degrees of pitch is reached. No one looks in....checks the AH, says Aha, 30 degrees of pitch...what is my speed and altitude ?
Lookout on way round....check wings level....just before the Apex, check the gate, then head back and watch the horizon come over the top already knowing if you've made the gate or not.

Personally I don't buy this 3700 / 2700 stuff.

[mrangryofwarlingham]

I imagine the CAA will at some point think long and hard before they let military single engine turbines over central London.

At 1300 ft down the mall.....more like below 1000ft temporarily to wow the crowds....the donkey stopping won't give the pilot much chance to respond....quick pull up to trade speed for height and reach best glide speed. And then see if it can be put down in the river. And eject just before putting it into the Thames.

But the CAA allows this on overcast days. VFR on top with no sight of ground with no donkey.....bad place to be.

[mrangryofwarlingham]

Treble one

Maybe.
For me it's a question of which is more likely.
Superb pilots having a bad day making a catelog of mistakes or something else.
AH was a superb pilot, most harrier pilots are the cream of the RAF.....so for me the chances of something else are more likely.

[Treble one]

Treble one

Maybe.
For me it's a question of which is more likely.
Superb pilots having a bad day making a catelog of mistakes or something else.
AH was a superb pilot, most harrier pilots are the cream of the RAF.....so for me the chances of something else are more likely.


MrA-I've met quite a few Harrier pilots who tell me the same-although I've not met AH. I have no doubt that you are correct-the Harrier guys were undoubtedly the ones who were above average during flying training.


But its worth remembering that AH was a Harrier pilot many years ago, and he was driving an Airbus or Boeing at the time of the accident, which is slightly different I imagine? And would not especially prepare you for low level aeros in a swept wing vintage fighter jet?


TO

[H Peacock]

For me it's a question of which is more likely.
Superb pilots having a bad day making a catelog of mistakes or something else.
AH was a superb pilot, most harrier pilots are the cream of the RAF.....so for me the chances of something else are more likely.

Ah, back to the 'too good to make a mistake'! And a Harrier pilot you say, well they never get it wrong! (mid-air over Wisbech; mini-cct at Wittering; GR5 over Bosnia; Flap-less t/o from the hide; departure on airtest; loss of oil but no urgency to land; throttle v nozzle lever at Lowestoft; UP from loft rec'y near Barnard Castle; deck landing into the sea abeam carrier; CFIT near Evesham; rec'y into Khandahar......) AH flew the Harrier over 20 years ago with a total of less than 600hrs. Was Southport AH just having a bad day or was that also down to 'something else'?

Very dangerous in aviation to conclude that someone is just too good to get it wrong. I've listed them before, but even looking at just the display scene where everyone is 'above-average', nearly every loss/accident is caused by driver error.

[mrangryofwarlingham]

HP

I didn't say he was too good to make a mistake.

[mrangryofwarlingham]

Treble one

Are all airbus and Boeing drivers nothing more than average? Does an above average pilot (and I think you will agree that the RAF have no shortage of applicants so they can choose the best) simply become a systems manager the day he takes off his RAF flight suit and puts on BA uniform?

Regarding low level aeros, what is it about preparation you feel he was lacking in?
Is there any relevance to this accident that the plane was a fighter? That it was swept wing?
Maybe this accident would have happened to him on this day regardless of the type he was flying.....if he got undemanded power reduction? Maybe he was so off his game on the day, that he would have struggled in a Cessna aerobat?

That he was off his game and made a catelog of mistakes is clear. The question is why? Was there something else ?
All I am saying in my view it is more likely that other factors were present.

[Treble one]

Treble one

Are all airbus and Boeing drivers nothing more than average? Does an above average pilot (and I think you will agree that the RAF have no shortage of applicants so they can choose the best) simply become a systems manager the day he takes off his RAF flight suit and puts on BA uniform?

Regarding low level aeros, what is it about preparation you feel he was lacking in?
Is there any relevance to this accident that the plane was a fighter? That it was swept wing?
Maybe this accident would have happened to him on this day regardless of the type he was flying.....if he got undemanded power reduction? Maybe he was so off his game on the day, that he would have struggled in a Cessna aerobat?

That he was off his game and made a catelog of mistakes is clear. The question is why? Was there something else ?
All I am saying in my view it is more likely that other factors were present.


Mr A-I drive a Ford Focus and I have a very good safety record in touch wood. However if I go away for the weekend and get into a high performance sports car, say, would that be the same?

I never said for one second that airline pilots were average. I contend that flying an Airbus or Boeing does not necessarily prepare you for flying a Hunter in low level aeros.

I also DIDN'T say he WAS underprepared etc etc-I said he MIGHT have been, just like you and others say he MIGHT have been incapacitated/impaired.

But was he incapacitated at the start of the manoeuvre when he was too low and slow? Or was he incapacitated on the way up, on the way down? He doesn't appear to be have incapacitated just prior to the crash when the attitude of the aircraft would indicate he was pulling very hard?

The engine? Red herring? There was a potential problem, but the report says that it didn't affect engine performance. Even if the engine was at fault, the pilot was still too low, still missed his gate, still didn't attempt to escape the manoeuvre. Surely if his day job is systems management and monitoring instruments, then this should have been a given?

I'm sorry-I'm the sort of chap who when he hears hooves thinks horse not zebras.

[LOMCEVAK]

mrangry,

In a swept wing (low aspect ratio) aircraft the angle of attack at which you fly results in far greater variations in induced drag than with a straight wing. Therefore, variations of overall energy during a looping manoeuvre are far greater in a swept wing aircraft than in a straight wing one. Because of this and the nature of the lift-curve at high angles of attack, it is far easier in a swept wing aircraft to pull up for a loop and fail to achieve the gate height. Rigid application of gate height protocols are essential for downward looping manoeuvres in a swept wing aircraft but are not really relevant to low speed, straight wing aircraft that have a high pitch rate at the apex.

In short, yes, it is very relevant that this accident occurred in a swept wing aircraft and, commensurately, previous swept wing aerobatic and display experience is also very relevant.

[RAT 5]

I understand cost in a private display organisation, but how often do display pilots practice their routines? I would suspect that different sites require different manoeuvres, and also often different allowed durations. If this assumption is correct then there could be 3 or 4 different routines in a pilot's portfolio. All need to be comfortable, especially at low level. This also includes having a 'flat display' option. The professional teams practice the full & flat display regularly, what about the solo guys?

[Treble one]

I understand cost in a private display organisation, but how often do display pilots practice their routines? I would suspect that different sites require different manoeuvres, and also often different allowed durations. If this assumption is correct then there could be 3 or 4 different routines in a pilot's portfolio. All need to be comfortable, especially at low level. This also includes having a 'flat display' option. The professional teams practice the full & flat display regularly, what about the solo guys?


RAT 5, civilian display flying is covered in CAP403-this covers many things including practices etc. It was tightened somewhat after this accident.


The pilot was fully in compliance with the terms of CAP403 when he flew this display, and all his DA and other paperwork were all completely in order, at the time.

[Whipstall]

mrangry,

Rigid application of gate height protocols are essential for downward looping manoeuvres in a swept wing aircraft but are not really relevant to low speed, straight wing aircraft that have a high pitch rate at the apex.

Failure to stick rigidly to gate heights will get you killed as quickly in a straight wing aircraft as any other type.

[mrangryofwarlingham]

Lomcevak

Thank you.
But did the AAIB place any specific emphasis on the plane being a swept wing type.
Or as Whipstall suggests more emphasis is placed on the failure to go through the gate....
I acknowledge that gates can be specific to aircraft type.

Treble one
HP

Why do you both have to copy previous posts when responding?
Are you the same person?

Treble one

I agree flying Airbus or Boeing does not prepare you for low level aeros in any type.
I agree with you there was a catelog of errors.
So what do your horses tell you regarding the reason for all these errors?
Would you care to suggest an explanation?
On one side of your face you say he was CAP 403 compliant.
On the other side you suggest he might have been underprepared.
And so what?
We have different views.
I have an opinion and you have yours.
But your view fails to address the question of why.

[H Peacock]

Treble one
HP

Why do you both have to copy previous posts when responding?
Are you the same person?

Mr A. I always put the quote in if I'm 'replying' to a specific post. If you don't it can be more confusing to others especially if there are additional posts from others between them. And no, I'm not Treble One; I've never served on one hundred and eleven squadron! ��

[Treble one]

Mr Angry


He was CAP403 compliant at the time-however the fact that CAP403 has been updated and tightened in terms of currency suggests that the CAA have decided that the display currency requirements and DA authorities needed tightening.


So maybe they didn't consider 40 plus hours on type in 5 years sufficient to perform this routine after all-or that the DA awarded valid for the Hunter based on a routine in a propeller driven aircraft wasn't quite what's required either?


He went into a manoeuvre too slow-Fact
He missed a height gate-Fact
He failed to realise it-Fact
He failed to address it by pulling out-Fact
He carried on despite everything-Fact
He crashed and was in no way incapacitated as he was clearly pulling like a rigger prior to impact-Fact


So you are contending he was incapacitated 'at some point' during the manoeuvre-When? How? Why? All contention. Speculation. Looking for reasons to explain a clear case of pilot error?

[hum]

111 - but I have to say that there is absolutely no evidence of cognitive impairment or incapacity to be a contributory factor in this accident
What would you consider as evidence of cognitive impairment or incapacity? You say there is none, how can you be so sure?

Maybe he had a bad day?
We all have a bad day from time to time, but it should not end up with such a tragic accident. This was more than just a 'bad day'..

Maybe he was complacent? Maybe he was ill prepared? Maybe he made a series of errors of judgement?
Then why did the AAIB not say so?

then everyone rushes to say that he was impaired or incapacitated.
No – if he was definitely impaired or incapacitated, would the AAIB not have concluded that? They have left the question unanswered, which can only mean (to me) they do not know. All I and others are suggesting is that such ‘a catalogue of uncharacteristic errors during a flying display’ is highly unusual (I cannot think of another display accident with such a sequence). As more ‘uncharacteristic errors’ become apparent, maybe we should look for a common link?

In fact the more I look at the sequence or events from a few seconds prior to pull up to a few seconds before disaster the less I see of anything a reasonably competent fully functional aerobatic display pilot would have done. :sad:

[Treble one]

Perhaps he just cocked it up?

[Lemain]

He failed to realise it-Fact

How is that a 'fact'?

[Treble one]

How is that a 'fact'?


Because he was 800 feet lower than he should be to hit his gate?

[Lemain]

Because he was 800 feet lower than he should be to hit his gate?

We don't know for a fact that the pilot didn't realise it. It's a fact that he didn't recover from it but we don't know for a FACT that he didn't realise it.

[DaveReidUK]

Because he was 800 feet lower than he should be to hit his gate?

That's true, but it doesn't necessarily follow that he failed to realise it, which was the statement of yours that the previous poster queried.

He may instead have judged that he still had sufficient height to complete the loop (and of course he was very close to being correct).

At the risk of being boring and quoting yet again from the report, the AAIB did indeed allude to this possibility and declined to rule it out.

[H Peacock]

He may instead have judged that he still had sufficient height to complete the loop (and of course he was very close to being correct).

Indeed you are probably correct DRUK, which I'm afraid means he shouldn't have been in that particular cockpit in the first place. If you miss a critical gate height by 1000ft or so and then decide to continue regardless then you shouldn't be a display pilot. How could the Shoreham Display organisers possible have allowed for such an eventuality?

[Treble one]

Gate heights and speeds-set in stone for FJ display pilots-otherwise why have them in the first place?

[H Peacock]

Gate heights and speeds-set in stone for FJ display pilots-otherwise why have them in the first place?

Nail hit clearly on the head with that, and also the conclusion of some immediately after the accident. Everything else in this tragedy secondary to gate height!

[mrangryofwarlingham]

Treble one

Yes. I can recite the facts to you too.

The question is why.
Is that such a difficult question ?

[Treble one]

Mr Angry-who knows.


Lack of experience on type/LL aeros in a swept wing aircraft?
Poor judgement?
Overconfidence?


Why does there have to be a reason? Other than he made a catalogue of errors?

[Lemain]

Why does there have to be a reason? Other than he made a catalogue of errors?

Because we owe it to the victims and their loved ones.

We owe it to the pilot who probably would rather not see his reflection in the bathroom mirror when he shaves every morning, for feelings of guilt.

All the while there is doubt we should continue to ask 'why?'. 'How?' And, at a mercenary level how can we be sure that the insureds' insurance companies provide decent provision for those so tragically killed. Maybe we will never know.

I personally don't believe the AAIB report goes far enough. Nevertheless, this is a place where people from all walks of life - victims, industry, engineering, and science can put their tuppenceworth into the hat.

Around 2/3 of posters here think it was basically pilot error. On the balance of probabilities they are probably right. However, the report has only recently been published and there is plenty of time for us to pick over the bones. There have been a number of recent posts that add fresh thinking.

There is no harm in letting people speculate. Surely that's what any forum bulletin board is about?

[Tay Cough]

Indeed you are provably correct DRUK...

Really?

There is of course the possibility that he realised full well that he hadn't achieved his gate and was physically unable to do anything about it until it was too late, at which point he attempted to recover anyway. Once again, difficult to prove though but no more or less valid than DRUKs opinion.

[Tailspin Turtle]

Interesting pic from another forum showing actual vs 'planned' (according to AAIB video) pull up..

http://i50.photobucket.com/albums/f318/gerryhum/image_zpsi9jy48x5.jpeg (http://s50.photobucket.com/user/gerryhum/media/image_zpsi9jy48x5.jpeg.html)

A very early pull, inapropriate throttle and aileron inputs, no escape attempt until a late pull very strongly suggest a transient cognitive impairment..

This illustration doesn't look right. Minor problem: the run-in should probably be along a line denoted by the radar hits. However, the actual pull-up had to be about as early as shown because bending the loop had to be done before reaching the extended show line. To start a pull up at the "planned" square would have put the upward side of the loop well inside of the show line, even farther in this instance because he rolled before being vertical. A comparison with the timeline in the AAIB report suggests that the actual pull up was somewhat later than shown by that square based on a comparison of the pull-up time and the radar-hit time. I still think based on the video that he probably pulled up later than he should have, not earlier, because he wound up tracking along A25 not crossing it parallel to the show line.

Incidentally, the margin of error given for the speed at pull up means that he could have been at 325 knots indicated, not 310. Still missing that gate and readily discernible on the airspeed indicator from 350 knots but 25 knots slow and not 40. He might have thought from experience that was fast enough and it might have been for a straight-ahead loop (i.e. no bending, particularly before being vertical), full throttle, and optimum timing and amount of pull.

[mrangryofwarlingham]

So families affected can understand why
so we can learn from the errors of others and prevent future accidents
To enhance safety

You seem to have another agenda
Ascribing blame

Not much value in that for me

[Treble one]

Mr Angry we've learned lots from this accident.

How important it is for display pilots to stick to their height and speed gates.
How important it is to be trained in escape manoeuvres if said gate heights and speeds are not met.

Two errors we can learn from?

[Tay Cough]

This illustration doesn't look right. Minor problem: the run-in should probably be along a line denoted by the radar hits.

Am I being picky? Radar is radar. The run in WAS along the line denoted by the radar hits (obviously?). According to the AAIB video, the green line shows where it should have been.

The pull-up was next to the bend in the river. The radar doesn't lie.

Neither does the camera. (https://m.youtube.com/watch?v=pvHplYmh2f8)

[Lemain]

Radars don't have perfect accuracy. If radar is to be used evidentially then the possible error on either side of the recorded track should be superimposed. There are several factors that affect the accuracy.

[DaveReidUK]

There is of course the possibility that he realised full well that he hadn't achieved his gate and was physically unable to do anything about it until it was too late, at which point he attempted to recover anyway. Once again, difficult to prove though but no more or less valid than DRUKs opinion.

Just for the record, I wasn't venturing an opinion, but simply quoting from the report.

But you are correct in that a number of the AAIB's findings contain an "either/or" where two or more alternative scenarios exist and the evidence is insufficient to determine which one is actually what happened.

[donotdespisethesnake]

Treble one

Yes. I can recite the facts to you too.

The question is why.
Is that such a difficult question ?

Pilots are human. Humans make mistakes. Are you asking why do humans make mistakes?
That's actually a pretty deep and complex question, seeing as no one understands how humans develop conscious thought in the first place.

[Lemain]

We make astonishingly few mistakes given our supposed weaknesses. When did you last have a car crash that was your fault? Almost all accidents follow a sequence of problems. I guess most of us here looked very hard at the Air New Zealand Flight 901 Erebus crash. Gordon Vette's Impact Erebus is a compelling read because of his careful research and, of course, coming from Captain Vette. For me, that narrative defines the chain of events leading to an accident - even if you don't agree with Vette's conclusions the line of reasoning is compelling. Impact Erebus is also a must-read for any pilot being both informative and gripping. My copy is pretty dog-eared now.

[H Peacock]

Well nearly every car crash Is going to be the fault of one or both drivers involved. Not sure how else they can happen.

Flight 901 is indeed chilling, but really does highlight the need to ensure you are - and stay - VMC if that is the intended plan! Never mind the excuse of not being where you thought you were, VMC is relying totally on the pilot to see ahead and keep clear of any terrain.

[Lemain]

Well nearly every car crash Is going to be the fault of one or both drivers involved. Not sure how else they can happen.

There might be a mechanical problem with one for the vehicles. Or both. There might be a problem with the road surface. One of the drivers might have been distracted.

Or one of the drivers might have had some kind of medical problem such as loss of consciousness. Would that, in your opinion, be a 'fault' of the driver or just a symptom of a body weakness?

[G0ULI]

Speaking from experience investigating accidents, it is extremely rare for any car accident not to be the fault of one of the drivers. Even in cases of sudden mechanical failure, that is usually down to deferred maintenance, the manner of driving, or ignoring warning lights io the dashboard. Sudden ill health is no excuse either. With the exception of a sudden massive heart attack, which generally happens after warning symptoms that have gone unrecognised, a vehicle can normally be brought to a controlled stop for help to be sought.

Misjudging speed or the severity of a bend is probably the number one cause of single vehicle accidents. Bears a remarkable similarity to the events at Shoreham, just in a vertical axis. (I was going to say plane, but that might have come across rather flippantly).

Looking back through my records, there isn't a single accident that I dealt with where blame could not be placed firmly on one or more of the drivers involved.

[hunterboy]

G0ULI, Out of interest, who was placing the blame? An insurance company or a court? I think many people have a low opinion of seemingly arbritary decisions made by car insurance companies that may/may not stand up in a court of law.

[scifi]

For those that say he was too slow in the inverted part of the Loop, I think you are missing the point that at slow airspeeds the radius of curvature will be SMALLER. So would have helped reduce the size of the loop.


Just to demonstrate the principle... Taken to the extreme, if his speed was over 500kts in the inverted, the possible radius of curvature would be enormous.
.

[G0ULI]

It was generally me or forensic examiners who were responsible for establishing the sequence of events. The paperwork then went 'upstairs' for a decision to be made on what further action to take. Insurance companies were not involved until much later in proceedings and frequently not at all, because there was no policy in force.

Short of a tree, building or aircraft suddenly falling on a vehicle, nearly all accidents are avoidable if a vehicle is driven in a manner appropriate to the road conditions at the time.

I don't have any problem with 'enthusiastic' driving under the right circumstances, but drivers must accept it carries a risk to themselves and other road users.

Same thing goes for air displays. Operating an aircraft near the boundaries of its performance envelope requires minute attention to detail and a clear assessment of the potential risks to the aircraft and those on the ground. That clearly didn't happen at Shoreham, or the risks and consequences were grossly underestimated on the grounds that no incident involving mass casualties had happened for decades.

[G0ULI]

scifi
Correct but for the fact that a certain minimum airflow over the wings and control surfaces is needed for the aircraft to remain airborne and controllable. Swept wing aircraft need more airspeed to avoid stalling than conventional straight wings.

[RetiredBA/BY]

Really ? Aerodynamics as taught by the RAF and a million others, as well as a lot of personal hands -on experience, tells me that stalling is a function of angle of attack not airspeed or have I been in ignorance since I started flying in 1960 in swept and straight wing jets !

...............and I thought this was a professional site !

[H Peacock]

Scifi. The speed needed at the top of a loop is dictated by several factors. If too slow then as G0uli correctly stated it becomes harder to keep accurate control of the aircraft, even if the AoA remains very low by unloading. Gravity helps you at the top by providing a 'free' +1g even if you are fully unloaded, but then you'll need more than +1g to finish the loop so you'll need to accelerate to get more speed as you descend. Therefore you clearly can be too slow at the top of a loop.

However, as you eluded to, you can also be too fast. To a certain degree the faster you are the more g you can pull, but the radius also increases so there does become an upper limit. Minimum radius is probably what you are after. Therefore, the apex gate parameters will invariably have a minimum height and a min and max IAS. The Hunter was just above the minimum speed, but not too slow.

The actual speed at the apex will obviously be a function of entry parameters, induced drag and radius. To a certain degree you can pull harder and hence be lower but faster at apex. Alternatively, a slacker pull will give you more height but at the expense of speed. Had the Shoreham Hunter used much less pull on the way up it may have been a little higher but also slower. Entering the loop too slowly also had a significant effect. Of course the change in induced drag with AoA can be considerable in a swept wing machine.

RBaby, I think you know exactly what G0uli was eluding too!

[Jesse Pinkman]

Theoretically, one's max rate turn is also one's min radius turn but for the inconvenience of compressibility. Yes, the radius of a turn will increase in relation to the speed of the aircraft if lift is not increased but the increase is linear. Up to the G limit of the aircraft at a fixed coefficient (fixed AoA if you like) however, the lift increases in relation to the square of the speed. So, while your speed may be increasing the size of your turn, the lift available to shrink it is increasing at a greater rate. So, min radius turn happens nowhere near the min flying speed, it happens at the point where max lift coefficient (light buffet) coincides with max structural load (g limit) when one is going very, very fast.

Too slow over the top is a very real problem because the lift formula being dominated by EAS squared and Lift Coefficient produces very little puff at low speed. Your 500kts scenario is also very bad though SciFi because at that speed the pilot would encounter structural limitations that precluded the achievement of max coefficient.

[DaveReidUK]

For those that say he was too slow in the inverted part of the Loop, I think you are missing the point that at slow airspeeds the radius of curvature will be SMALLER. So would have helped reduce the size of the loop..

Quite so. That, like most of the points made in this thread (with the possible exception of the vehicle accident analogies) is explicitly made in the report.

Which in turn raises the interesting scenario that the pilot may have been aware of both the low apex height and airspeed, but judged that the lower than planned height loss that would result from the low apex airspeed would still allow safe completion of the loop manoeuvre.

[sika hulmuta]

But he would also have known that to achieve a best solution he would require max thrust. Which he didn't have.

I believe he was confused or unaware, for whatever reason, when he pulled through.

[Machinbird]

I believe he was confused or unaware, for whatever reason, when he pulled through. That is my opinion as well.
I may have missed it, but the accident report doesn't seem to cover the pilot's actions on the day of the accident leading up to the flight in great detail, specifically, when he ate, what he ate and how much time elapsed subsequently.
This can have a bearing on hypoglycemic events that some people will have a predisposition for.
I remember an interesting case of an F-8 wingman joining on the lead aircraft after takeoff from NAS Miramar, when he went blind during the rendezvous! Fortunately the lead got him in sight quickly and gave voice commands which he was able to follow. After a while, his vision began coming back and the aircraft was recovered into the arresting gear at NAS Miramar. The sawbones blamed the problem on hypoglycemia resulting from a coffee and donut fighter pilot breakfast.

[abgd]

Hmm Gouli. Locally some of our road accidents have involved incapacity (Parkinson's and a cardiac arrest) a falling tree and a patch of oil leading to loss of control at an unusually low speed.

Of course a lot of them have involved alcohol or exuberant driving as well but the idea that mishaps that are not due to driver error are rare seems to me to be incorrect.

Tbh the more I think about this event the more I feel that wipe-outs at low level are inevitable. It doesn't mean there are no improvements to be made in pilot performance, but perhaps air displays with jets should only take place over the coast or moors. Focusing unduly on the pilot seems to me, unproductive.

As a spectator I'd far rather some measured approach like this, than a blanket ban or overly restrictive minima leading to displays that are too far away to see.

[DaveReidUK]

But he would also have known that to achieve a best solution he would require max thrust. Which he didn't have.

That's interesting.

Your statement seems at odds with the test flying reports that, once at the apex, thrust setting makes no significant difference to the height required for recovery:

"... the minimum radius loop tests showed that power had little measurable effect on looping radius during the downward porttion when flown with an AOA for maximum usable lift"

"... at the apex the power was varied between idle, which was less than in the accident manoeuvre, and maximum which, in the F Mk58, was greater than that available in G-BXFI. Significant differences (80 KIAS) were seen in the speed at the end of the manoeuvres as a function of power setting past the apex but power did not have any significant effect on the height loss with the exception of the final loop with 2 notches of flap when maximum power may have reduced the height loss slightly"

[Madbob]

GOULI


I agree that having an excess of speed over the top would have given AH increased options to abort the bent loop. I.e. more lateral control to roll out without the same risk of an inverted departure....


Too slow and the radius of the last quarter increases and one is left with no control other than to mush into the ground which is what sadly happened.:(The only thing that might have saved the situation might have been to jettison the 100 gal droppies:( which still contained fuel. But they would have landed on the innocent victims in much the same location as where the Ac crashed.....


MB

[G0ULI]

abgd

I agree that there is always going to be some element of risk inherent in air displays. I certainly don't want to see a ban either. Part of the excitement, to me, is the perception that there is a slight element of danger, as a spectator. It is no different to some of the more extreme rides at amusement parks. The element of danger to the riders appears far greater than it actually is. But we do not expect parts of these rides to fall onto spectators away from the immediate ride area, or outside the boundary fence of the amusement park.

Technical failures happen, pilots make errors of judgement. It is up to the organisers of air displays to ensure that where an accident happens, the effects are contained within the airfield boundaries or over unpopulated areas such as the sea or open farm land. This will inevitably affect the ability of some airfields to be able to hold air displays at all due to urban developers tendency to build right up to airfield boundaries.

Commercial aviation is by no means free from similar failings as demonstrated at Kegworth and Heathrow, where busy motorways run directly across the main runway approaches.

[Lemain]

Neil Williams crash 11Dec1977

I was flying all that day at Blackbushe when the news came in. Doug Arnold had been driving up the runway and taxiway in his Roller, setting fire to some dead grass. He was a very unusual man. I found him easy to do business with as long as you did as he told you :ok: Neil was due in with Doug's latest acquisition for War Birds of Great Britain, a Spanish-built He 111. I didn't know that Neil was due in, but during the day RT with the tower became more tense.

Neil Williams was regarded as one of the finest pilots in the world. He flew his aircraft into the ground. No survivors. Here's a thread from another forum Neil Williams crash 11Dec1977 (http://forum.keypublishing.com/showthread.php?105583-Neil-Williams-crash-11Dec1977) It's bad form and etiquette to post a link to a competitor forum so I quite understand if mods and admin here on Pprune delete it. However, it does tell a story that is relevant to this thread and for those who don't know the story, it is worth a read.

[Hebog]

Can an experienced display pilot explain the following :-


[FONT=Arial][SIZE=3][COLOR=#231f20][FONT=Arial][SIZE=3][COLOR=#231f20]The resultant periods between the pull-up and the apex at the Shoreham 2014 and 2015 Airshows overlap.


However, when the videos of the ‘bent loop’ manoeuvres were viewed side by side, it was observed that the first half of the Shoreham 2014 ‘bent loop’ had a slightly higher pitch rate and was completed in a slightly shorter time than the first half of the Shoreham 2015 ‘bent loop’.


Engine speed during the loop at Duxford in 2014 was approximately the
maximum allowable throughout the climb. The Shoreham 2014 manoeuvre was initiated with a low engine speed which then stepped up in two stages, levelling at slightly under 8,000 rpm for the last part of the climb. The climb for the accident manoeuvre was initiated with an engine rpm approximately half way between the initial engine rpms of the other two manoeuvres. The engine speed then reduced to below 7,000 rpm, recovered to and briefly heldat 7,250 rpm, and then reduced further, passing below 7,000 rpm at the apex.


At the apex of the accident manoeuvre, the engine speed was approximately 1,000 rpm lower than for the other two manoeuvres. A further distinction of the accident manoeuvre is that the engine speed increased during the descent whereas during the other two comparison manoeuvres the general trend was a reduction in engine speed.


Would an experienced pilot changed the way he was controlling the throttle during a manoeuvre so that it was nearly the opposite. As far as I can tell this indicates to me that AH was not flying as 'usual' or there were other factors involved, which haven't been identified as yet.

[DaveReidUK]

Too slow and the radius of the last quarter increases

That seems counter-intuitive. The lower the speed, the tighter the radius for the same amount of g.

[G0ULI]

But in order to pull the G you need sufficient speed to generate the aerodynamic lift required.

[RetiredF4]

To bring some sense into the discussion about the effects of speed in relation to turn radius.

http://people.clarkson.edu/~pmarzocc/AE429/AE-429-12.pdf

[LOMCEVAK]

Lemain,

You say "I personally don't believe the AAIB report goes far enough". Within the remit of AAIB reports, which present data and analyse it, what else do you think should have been included? Opinion and speculation are quite deliberately, and correctly, not included in their reports.

[Lemain]

Hi LOMCEVAK

Lemain,

You say "I personally don't believe the AAIB report goes far enough". Within the remit of AAIB reports, which present data and analyse it, what else do you think should have been included? Opinion and speculation are quite deliberately, and correctly, not included in their reports.

Yes, and no. Unless there is some initial speculation vital clues and evidence can be missed. For example, the pilot's qualifications and medical are looked into speculatively. In this AAIB report there are some odd omissions. For example the radar track is taken as gospel. Did a radar expert check the system? There is no measuring system in existence that is 100% accurate - factors such as antenna location, nature of antenna, and the digital processing can be important. I don't see any explanation in the report yet the radar track is considered evidential.

[windytoo]

The blame game being played by certain contributors over the last few pages is predictable but a little sad to read.
Over the last 20+ years display aircraft have been moved further and further away from the display line and more restrictions have been placed upon dynamic manoeuvres towards the crowd. There is always room for improvement, modernisation and organisation on the airfield, but if high performance aircraft are to be displayed then complete safety off the airfield can never be guaranteed.
In this horrible situation at Shoreham, the people killed innocently driving past were incredibly unlucky but the group of people standing next to the Police sign saying "No Stopping Here" were very foolish. Inside the airfield perimeter they would have been on or very close to the display line, which obviously would not have been permitted. Unfortunately therefore they must accept some blame towards their own demise.
Although this sounds incredibly callous I believe the insurance companies involved will take this into account in their deliberations.
100% safety on but especially off the display area can unfortunately never be achieved.

[Ian W]

Am I being picky? Radar is radar. The run in WAS along the line denoted by the radar hits (obviously?). According to the AAIB video, the green line shows where it should have been.

The pull-up was next to the bend in the river. The radar doesn't lie.

Neither does the camera. (https://m.youtube.com/watch?v=pvHplYmh2f8)

Radar can easily 'lie' dependent on its scan rate and the rate of change of vector of the aircraft. I have seen aircraft apparently orbiting left on radar but actually orbiting right - due to simple stroboscopic effect. Similar "lies" (artifacts is a better word) are possible with cameras https://www.youtube.com/watch?v=yr3ngmRuGUc (https://www.youtube.com/watch?v=yr3ngmRuGUc)
Radar maps can often be 'adjusted' to match (or not match) the physical position of airports, it was only after ADS-B was brought in that some misalignments were found at some airports. With awareness of those possibilities it is also important to ensure that the raw radar data is considered as processing can also add similar artifacts

[LOMCEVAK]

Lemain,

The pilot's qualifications and medical are fact - there is documentary evidence. With respect to the causal and contributory factors, why was greater analysis of the radar track accuracy required? The workload in producing a report such as this is immense. Therefore, if something is of academic interest and not totally relevant to establishing the causes of an accident then why spend time on it.

[Lemain]

Yes, of course the qualifications and medical are facts. But it was speculation that the pilot might have been under qualified or not medically fit that made the investigating team check that out. I realise this seems pedantic and I chose the quals and medical because it's so obvious. You cannot investigate without speculation.

Moving on the radar track: The report draws upon the radar track to support the conclusions. Once introduced as evidence, the AAIB should have considered whether that evidence is accurate. We know that no measurement system is 100% accurate so there must be tolerances. Maybe the AAIB did consider those. Maybe they didn't. But they should have mentioned it in the report.

I'm not arguing that there was, necessarily, any significant error in the radar track. I'm casting doubt about the competence and diligence of the AAIB team that issued an accident report.

[H Peacock]

Lemain, I'm not sure where you are trying to go with your concern about the radar data accuracy. There is plenty of video evidence of the manoeuvre, and the exact ground track flown bears no bearing on the cause of the accident. Do you want the AAIB to go into minute detail on every piece of evidence they have used, state it in the report and explore the almost infinite variation of every tolerance? How many more pages did you want??

[eal401]

the group of people standing next to the Police sign saying "No Stopping Here" were very foolish.

I would imagine the police sign referred to motorised traffic, unless it clearly specifies otherwise in either the nature of the signage or the regulations.

But nice effort to blame them for their deaths. :ugh:

[DaveReidUK]

But in order to pull the G you need sufficient speed to generate the aerodynamic lift required.

The OP is referring to the final quarter of the loop, i.e. after the aircraft has passed through the downward vertical.

I can't see airspeed being a problem there.

[Lemain]

Hi H Peacock

Lemain, I'm not sure where you are trying to go with your concern about the radar data accuracy. There is plenty of video evidence of the manoeuvre, and the exact ground track flown bears no bearing on the cause of the accident. Do you want the AAIB to go into minute detail on every piece of evidence they have used, state it in the report and explore the almost infinite variation of every tolerance? How many more pages did you want??

I was simply using one example to show that there was lack of due diligence in the report. The AAIB has not been as critical of their report as they should have been. For example just one sentence addressing the accuracy of the radar data might have sufficed. They considered the accuracy of the ASI and altimeters in some detail. Yet they introduce radar evidence without explaining what the tolerances are. How difficult could that have been?

If the argument is that the radar track is irrelevant why put it into the report? They could have said that they considered it irrelevant and left it there. All evidence must be subject to scrutiny and criticism particularly since lives were lost.

[H Peacock]

But the accuracy of the ASI and altimeter potentially have a direct and significant part to play. They were being used by the pilot who crashed. If they found the altimeter over-read by a 1000ft that would have explained why the loop was continued. The accuracy of the radar plots had nothing to do with what Andy and his T7 did that day; however, the radar track is relevant to the inquiry.

Do you want to know the experience and currency of the lead AAIB Inspector, just in case that is relevant?

[Hebog]

The ASI and Altimeter were tested on the bench and were found to be working fairly accurately. However, the aircraft system couldn't be tested due to damage nor could they be seen in any footage to confirm that they were fully operational either. So it is an assumption that they were and the pilot either ignored them, mis-read them or carried on regardless, therefore, only one of these could therefore be fact but which one.


I agree there are chunks missing from the AAIB report, such as due to the seemingly poor maintenance standards (out of date cartridges, MPD's not complied with, part no incorrect, faulty G counter and unknown servicing schedules) in the last 6 years that have been highlighted by the report. It seems odd that the CAA have not given more of an in depth report on the standard of the rest aircraft frame. After all the seat cartridges being out of date are irrelevant to why, as is the compliance of the MPD if this wasn't the why. I know they are solely to recommend improvements for safety but an aircraft poorly maintained or not to standard is a safety risk. They seem to have gone through the pilots info with a fine toothcomb and his log books but not so much on the aircraft and its books.

[Lemain]

.... The accuracy of the radar plots had nothing to do with what Andy and his T7 did that day; however, the radar track is relevant to the inquiry.

Do you want to know the experience and currency of the lead AAIB Inspector, just in case that is relevant?

If the radar track is, as you say, relevant to the inquiry then surely the accuracy of that track is relevant?

[Magplug]

In my personal view I don't think this will ever be put forward to trial by the CPS. Whilst there is a lot of public pressure because there were tragic deaths and 'somebody must pay', the burden of proof has many holes in it.

To be found guilty of 'Manslaughter by gross negligence' you have to show that the defendant wilfully ignored information that might have caused another competent pilot to take a different, safer course of action. This must be proven 'beyond any reasonable doubt'.

- The pilot was correctly licenced but was not required by the authority to carry out his display revalidation on every type he was to be licensed.
- His display training mandated by the authority did not include an 'escape manoeuvre' from inverted exits at low level, nor was he required to be tested on same.
- The maintenance history of the pitot & altimetry systems was found to be incomplete with instances of unidentified controlled components found fitted.
- This airframe had a history of altimetry issues which might have affected both airspeed and altitude indications.

The way I see it there is ample 'Reasonable Doubt' in this case. There may be a lot of public pressure for a conviction but the CPS has to ask if there is any remote prospect at all of a guilty verdict.

[sika hulmuta]

The OP is referring to the final quarter of the loop, i.e. after the aircraft has passed through the downward vertical.

I can't see airspeed being a problem there.

The Hunter is a swept wing aircraft, and indeed I'm sure the TP's are right about turn radius, when the aircraft is flown accurately on the light buffet.

However, should the pull be continued into heavy buffet, which would be easy to do, the aircraft will continue to turn, but energy is being washed off at a very rapid rate. The available speed, hence G, will be less. The only safe way is to keep pumping energy in with max thrust, and keep flying the light buffet. Jesse Pinkman gave a very clear explanation why earlier.

[LOMCEVAK]

Lemain,

You say "But it was speculation that the pilot might have been under qualified or not medically fit that made the investigating team check that out". I disagree; qualifications and medical fitness are de facto potential causal factors that have to be checked in any such accident. They did not just check these because there was speculation about these being potential causes in this case.

You also say "If the radar track is, as you say, relevant to the inquiry then surely the accuracy of that track is relevant?" The radar track was relevant but within the uses for it (building awareness of the display pattern) then numerical accuracy was not. There are no conclusions, causal or contributory factors in the report that are affected by numerical accuracy data for the radar track.

[DaveReidUK]

The Hunter is a swept wing aircraft, and indeed I'm sure the TP's are right about turn radius, when the aircraft is flown accurately on the light buffet.

However, should the pull be continued into heavy buffet, which would be easy to do, the aircraft will continue to turn, but energy is being washed off at a very rapid rate. The available speed, hence G, will be less. The only safe way is to keep pumping energy in with max thrust, and keep flying the light buffet. Jesse Pinkman gave a very clear explanation why earlier.

I'm happy to accept all of that.

My original point was simply speculating about whether the pilot judged that his relatively low speed at the top of the loop would mitigate the low apex height by allowing a tighter radius in the second part of the manoeuvre.

We don't know whether he thought that or not, though we know that if he did, he was mistaken.

[LOMCEVAK]

DRUK,
A maximum IAS is usually applied to a gate height due to the increase in radius but I have never known of a gate height being lowered because of reduced radius at low speed. As has been mentioned before, min radius speed is not as slow as you can get.

[G0ULI]

Reviewing various videos of the flight, I see a slight hesitation in pitch as the aircraft is descending through the vertical. The pitch change seems to stop for just a second or so before continuing. This might be a video artifact, the pilot realising he has a big problem, or simply the angle between the camera and the aircraft.

It may be that the hesitation was an attempt to maximise airspeed in order to pull a higher G recovery in the final quarter of the loop. I don't think it has a great deal of relevance to the final outcome, but it might serve to indicate that the pilot was fully aware that there was a problem at that point and was doing his best to try and recover the situation.

It also might suggest that the pilot was trying to invent a recovery procedure without having trained for that eventuality before hand.

Lemain

I must take issue with you suggesting that the AAIB investigators were not completely competent and exercising due diligence throughout this investigation. Such comments are unworthy of this forum.

[Chronus]

Magplug thinks it will not get to trial and lists the reasons. From what little has so far been published about AH, it would seem to me a plea that he is not fit for trial may well be in store. Is it not the case that he cannot remember anything about the whole incident, from start to finish and cannot therefore comprehend what the whole fuss is all about.

[G0ULI]

Amnesia is not a defence, in law.

[Chronus]

Beg to disagree with my learned friend. A defendant suffering from amnesia may not be tried if his lack of memory of the events surrounding the crime prevents an adequate defense.

[DaveReidUK]

Is it not the case that he cannot remember anything about the whole incident, from start to finish and cannot therefore comprehend what the whole fuss is all about.

Even if the first part is true, it does not necessarily imply the second.

[Tailspin Turtle]

Reviewing various videos of the flight, I see a slight hesitation in pitch as the aircraft is descending through the vertical. The pitch change seems to stop for just a second or so before continuing. This might be a video artifact, the pilot realising he has a big problem, or simply the angle between the camera and the aircraft.

It may be that the hesitation was an attempt to maximise airspeed in order to pull a higher G recovery in the final quarter of the loop. I don't think it has a great deal of relevance to the final outcome, but it might serve to indicate that the pilot was fully aware that there was a problem at that point and was doing his best to try and recover the situation.

It also might suggest that the pilot was trying to invent a recovery procedure without having trained for that eventuality before hand.

Lemain

I must take issue with you suggesting that the AAIB investigators were not completely competent and exercising due diligence throughout this investigation. Such comments are unworthy of this forum.

I noticed the apparent hesitation on the backside of the loop as well and surmised earlier that since he appeared to be somewhat south of where he intended to be, he was thinking (analyzing in AAIB terms) instead of pulling while he was orienting himself and/or deciding how to regain position for his flyby north of the show line. It also suggests a lack of urgency at that point about pulling out - either he didn't check his gate height or misread it as has been suggested.

The time to accelerate to cornering speed is immediately after coming over the apex; he should have had plenty of speed by the time he was going straight down. I was surprised that the AAIB report of test flights did not show any benefit of different flap settings or power changes in minimizing altitude loss on the backside of the loop. In any event, accelerating straight down and not pulling when you think you might not make it would definitely be counter-intuitive at that point.

[H Peacock]

I was surprised that the AAIB report of test flights did not show any benefit of different flap settings or power changes in minimizing altitude loss on the backside of the loop.

TT. Have you not read Annex H {para 15 c (1)-(4)}. It's all there!

[G0ULI]

Chronus

With the deepest respect, while amnesia may be considered grounds for not commencing proceedings if a defendant is incapable of mounting a defence against the charges and there is no independent supporting evidence, amnesia in and of itself is no defence against charges being brought, nor a defence against conviction in English Law. Amnesia may be taken into consideration when deciding any sentence upon conviction.

The reasons behind this are that amnesia can be faked. There is no way or reliable medical procedure for determining if the claimed amnesia is genuine or not.

Remember that a trial is intended to determine whether the accused is guilty of the offence and whether they had an intention of committing the offence before or at the time it happened. The fact that you hit your head and suffered amnesia escaping from the scene of an armed robbery would be no defence in law. Having been convicted of the offence through forensic or CCTV evidence, a judge may rule that the person so convicted serve a reduced sentence in the grounds that they couldn't remember the event. BUT at the time the event happened, that person clearly had it in mind to commit a robbery, or other offence.

So I reiterate, amnesia is no defence, in English Law and in most other jurisdictions around the world.

[Treble one]

That is my opinion as well.
I may have missed it, but the accident report doesn't seem to cover the pilot's actions on the day of the accident leading up to the flight in great detail, specifically, when he ate, what he ate and how much time elapsed subsequently.
This can have a bearing on hypoglycemic events that some people will have a predisposition for.
I remember an interesting case of an F-8 wingman joining on the lead aircraft after takeoff from NAS Miramar, when he went blind during the rendezvous! Fortunately the lead got him in sight quickly and gave voice commands which he was able to follow. After a while, his vision began coming back and the aircraft was recovered into the arresting gear at NAS Miramar. The sawbones blamed the problem on hypoglycemia resulting from a coffee and donut fighter pilot breakfast.


Your body has glucose stored as glycogen-if you are short of glucose, glycogen gets converted to glucose as your body obviously needs the glucose for energy. Glucose levels in non diabetic patients are well regulated by the body and carefully controlled in a narrow band.


It would be a highly unlikely scenario that a pilot with an appropriate medical category to fly a fast jet would become hypoglycaemic in the cockpit during a display.

[Tailspin Turtle]

TT. Have you not read Annex H {para 15 c (1)-(4)}. It's all there!

Yes I read it - On page 11 of Appendix H it is written that "The height loss appeared to be insensitive to whether 1 or 2 notches of flap were selected and to the power setting". Which is why I wrote that I was surprised that there wasn't any benefit. I had assumed that both pulling the throttle back and adding flaps would reduce the altitude lost. I wasn't sure whether extending the speed brake would provide some benefit but that wasn't mentioned or I missed it.

[Machinbird]

Glucose levels in non diabetic patients are well regulated by the body and carefully controlled in a narrow band. It would be a highly unlikely scenario that a pilot with an appropriate medical category to fly a fast jet would become hypoglycaemic in the cockpit during a display.
Treble one, As we age, the close regulation becomes less effective. I see that effect in myself, although I have good scores on physicals and would probably still be medically qualified to act as a commercial pilot.
Perhaps you are still too young to have encountered the issue?
AH was no longer a spring chicken, was he? Do you know what he had for nourishment the day of the accident?

[Legalapproach]

Chronus, you're wrong and G0ULI is correct. The fact that a person cannot mount a positive defence because of amnesia would not prevent a trial. In fact there are many cases such as dangerous driving where exactly that happens.

[Jwscud]

I believe there will be charges, as the climate in the U.K. has been that way for some time. See Ouzo/Pride of Bilbao in shipping, and the recent Tiger Moth crash trial.

That both ended in acquittals does not suggest a huge chance of a conviction in this case, especially given the circumstances.

[Lemain]

Ouzo/Bilbao case was very different. The Officer On Watch saw the yacht and just steamed on without checking that the Ouzo was OK. Three yachtsmen were killed. There was a manslaughter charge made against the OOW but the jury couldn't agree whether it was the Bilbao that hit the Ouzo or another ship known to have been in the vicinity. Had the jury agreed it was the Bilbao the OOW would have undoubtedly been imprisoned.

[Treble one]

Treble one, As we age, the close regulation becomes less effective. I see that effect in myself, although I have good scores on physicals and would probably still be medically qualified to act as a commercial pilot.
Perhaps you are still too young to have encountered the issue?
AH was no longer a spring chicken, was he? Do you know what he had for nourishment the day of the accident?

I am technically a type II diabetic and indeed I researched into diabetes for two years so yep I'm aware of the issues. I have also suffered hypos and they are quite scary. I certainly wouldn't have attempted to perform LL aeros in a jet if I'd felt like that frankly.

So incapacitation due to hypoglycaemia at the top of a loop? Blimey those holes in that cheese.....they really were against him.

PS if he was hypoglycaemic this would have shown in the inevitable blood test he would have had on admission to A and E after the crash. Possibly even checked on site by the attending paramedics and doctor too.

[LOMCEVAK]

With respect to the apparent reduction in pitch rate observed on the videos of the accident manoeuvre there are a few point to consider.

When a looping manoeuvre is viewed head on, or when there is a significant planform aspect, the observer's perception of pitch rate is based on the rate of change of apparent fuselage length (nose-to-tail length measured tangential to the sightline). The relationship of this length and absolute fuselage length is a function of sine(pitch attitude). Therefore, for a constant actual pitch rate the perceived pitch rate will reduce passing a pitch attitude of 90 degrees (up or down). This is why this apparent phenomenon occurs on many of the videos.

In the report there is a plot of pitch attitude vs time to impact (Figure 13) commencing at 90 deg nose down. A straight line can be drawn through the error bars from 90 to 0 deg, indicating a constant pitch rate. Even if the data points are joined a significant pitch rate exists at 90 deg nose down. Therefore, if a reduction in pitch rate did occur it would have to have been significantly before the down vertical line in order for the pitch acceleration phase back to a significant, steady state pitch rate to be completed by the down vertical.

The aircraft had achieved a level pitch attitude before impact with a rate of decent at impact which was survivable by the pilot. The height loss data presented in Appendix H indicates that a maximum instantaneous pitch rate pull through was required in order to achieve the radius of the accident manoeuvre. Therefore, if there had been any reduction in pitch rate from this during the downward half of the manoeuvre then a higher rate of descent impact with a nose down pitch attitude would have occurred.

Based on the above, there appears to be no evidence to support a postulation of a reduction in pitch rate during the downward half of the manoeuvre.

[DaveReidUK]

Therefore, if there had been any reduction in pitch rate from this during the downward half of the manoeuvre then a higher rate of descent impact with a nose down pitch attitude would have occurred.

In fact the aircraft was in a stalled condition during the last few seconds of the manoeuvre, with a roughly 14° nose-up attitude at impact.

[Blacksheep]

But it was speculation that the pilot might have been under qualified or not medically fit that made the investigating team check that out.Absolute nonsense. Crew qualifications, currency, recent flight history and medical status are standard inclusions in all air accident investigations.

[Lemain]

Hi Blacksheep

How does that make it any less speculative? All investigations - science, engineering, accident - start out at time=0 as speculation. Writing down a checklist for convenience doesn't change that. However I was really trying to make the point that as you speculate and gather facts you must challenge the facts you've gathered. Following from that, when 'facts' are introduced without critical evaluation something is going wrong.

There are a number areas where the data (information) gathered seems not to have been self-criticised by the AAIB team. e.g. the accuracy of the radar track which was introduced by the AAIB without (as far as I can see) any accuracy challenge.

Why didn't the report explain why they didn't consider the accuracy? Radars do 'lie' - well there is always some potential inaccuracy. Another poster has commented that the radar track isn't relevant and another says it is. It's EDIT:[i.e. the relevance to the accident investigation] outside my competence but I do understand radar technology quite well.

[LOMCEVAK]

Lemain,

I think that the issue here is actually the definition of the word speculation. The Oxford English Dictionary one is: "the activity of guessing possible answers to a question without having enough information to be certain". The investigation of known potential causes (ie. currency, qualification, medical category) is not 'guessing possible answers'; the answers come from facts discovered by investigation. Therefore, I think that much of the exchanges here between you and others (including me) is because you are applying a different meaning to the word 'speculation' than the rest of us. This is not a criticism but, perhaps, speculation on my part!

I also am interested in what significance you think that radar track data accuracy has upon the conclusions in the report. Again, not a criticism but curiosity on my part because you do seem to keep returning to this issue with gusto.

[DaveReidUK]

But it was speculation that the pilot might have been under qualified or not medically fit that made the investigating team check that out. I realise this seems pedantic and I chose the quals and medical because it's so obvious. You cannot investigate without speculation.

On the contrary, investigation is the antidote to speculation.

[Lemain]

Hi LOMCEVAC

It's probably my lack of care in choosing the right words. All I'm trying to say is that evidence introduced into a report should be accompanied with a critical evaluation - if only as a footnote or appendix. It is certainly hard to read sequential posts and keep context -- one tends to pick up on specific sentences and paragraphs which then tend to take a life of their own!

I believe the AAIB report is below the standard that the victims, industry and the pilot deserve.

As an illustration of that I pointed out that the accuracy of the radar track in the report is not discussed. That is just one illustration. There are others.

I have no idea of the significance of that to the conclusions - I am not competent to comment on the flying having (sadly) never flown a fast jet.

But, the lack of scrutiny concerns me.

[LOMCEVAK]

Lemain,

By your own admission you have little or no subject matter expertise. Therefore, you are not qualified to make any comment on the standard of the investigation or of the report or the competence of AAIB, although you are entitled to your own opinion. However, speculative criticism of a team who have worked long and hard for almost 2 years to produce what is undoubtedly one of the most in depth AAIB reports ever is totally unjustified. If the experts deem that an item is not relevant, eg. radar track accuracy, then why would it be included in an already large document? Reporting should follow the tenets of Clarity, Brevity and Relevance. In a complex investigation such as this, brevity stills runs to 452 pages. Any additions of irrelevant comments would make the report even harder to digest for victims, industry and the pilot.

[Lemain]

Lemain,

By your own admission you have little or no subject matter expertise. Therefore, you are not qualified to make any comment on the standard of the investigation or of the report or the competence of AAIB, although you are entitled to your own opinion.

OK. Fine. I'll leave you to yours :)

[H Peacock]

Lemain

Let's try go put this radar issue to bed. The AAIB used the radar data along with video evidence to produce a track of the aircraft. The radar helped confirm the positioning of the Hunter from the few returns used. Furthermore, the report clearly states the limitations in using the radar data to 'track' a dynamic display (page 72-73) and the associated mode C info. Does anyone need to know (say) that the radar return on the run in was 20m further west? No, not relevant.

The bent loop was clearly depicted on several videos from various locations. There was no dispute about where the aircraft tracked. Again, does an error in the radar data have any impact on anything! No.

The radar data was used by the AAIB as a tool. The limitations in using the data was clearly shown.

The ASI & altimeter were accurately bench tested. Do we need to know the accuracy of the pressure test set used? What about the 115vac 400Hz supply they used, could that have had an effect on the bench testing? What about the post accident engine strip data from Rolls; do they need to include all the caveats with the methods they used to produce that data?

I'm not trying to beat you into submission, but can assure you that any errors on the radar data used by the AAIB have absolutely no bearing any possible conclusion to the accident.

[Chronus]

Amnesia.

I have not put forward that as a defence against charges. I have suggested it as reason for not being able to stand and be tried for the offence(s). What does amnesia mean. It may well represent a mask, a symptom of much more serious underlying psychological disturbance/ condition resultant from the accident whereby a reasonable defence cannot be mounted against the charges. Just try and imagine what AH may actually seen out of the wind shield of his aircraft in the last few seconds before the crash. Could he have not seen a crowd of people and vehicles in the path of his doomed aircraft. Could he have been oblivious to his own imminent death and of all those standing transfixed with faces up turned to the sky, moments before their lives were extinguished in front of him on the ground. When did the mercy of unconsciousness remove the horror of such an image from his mind. But what was it replaced with. I cannot conceive any normal human being not being affected by such a tragedy, particularly the person who has the capacity to feel any sense of responsibility for being an instrument for its cause. The question therefore is the nature and extent of the injury or trauma that such a person may have suffered. If such a person has by reason of such trauma, be reduced to such a pathetic state as a blabbering idiot or a catatonic moron, then would any court stand him up and try him. Perhaps a court in some demonic regime might do just that, but I doubt any over in our neck of the world would. So perhaps it is over to the shrinks and the lawyers to decide what next, with the police somewhere in between the two to decide what next.

[n305fa]

Lemain

As I've said before, AAIB reports do not contain a comprehensive description of every test, data validation process, theory or idea that was used/investigated and deemed "in their expert opinion" to be omissable from the final report. If they did report everything thereport would probably be the size of Lord of the Rings! It's really easy for Armchair experts like us, with no real understanding of the AAIBs internal processes and rigour, to pick holes in the end result of what must be a ridiculously complex process.

[dsc810]

It seems a strange argument that because a person cannot or more importantly "claims" they cannot remember anything we can not put them on trial.
It seems to lead to an open door on everyone claiming amnesia!

For example a lorry driver who wipes out yet another family on the A34 in Oxfordshire (which is becoming a regular occurrence now) simply claims amnesia of the event and we all say that fine you can go, no trial is necessary as we cannot try them.
What happens if he claims amnesia - but actually there is cab-cam (which in all the recent fatals there has been) which records him piling into the rear of the said family of 4? Does the availability of other evidence now render the alleged amnesia in this example irrelevant and we can put the person on trial.

It also leads to the strange situation where a person can escape justice by virtue of his brain makeup being susceptible to suffering from amnesia while say another person who does is not susceptible in such a way can be put on trial.

You may recall that Ernest Saunders managed to pull something similar off in his finance related trial...and succeeded in being released early as part of the appeal process due to supposedly having Alzheimers whereupon post release a miraculous recovery ensured.

[aox]

For example a lorry driver who wipes out yet another family on the A34 in Oxfordshire (which is becoming a regular occurrence now) simply claims amnesia of the event and we all say that fine you can go, no trial is necessary as we cannot try them.
What happens if he claims amnesia - but actually there is cab-cam (which in all the recent fatals there has been) which records him piling into the rear of the said family of 4? Does the availability of other evidence now render the alleged amnesia in this example irrelevant and we can put the person on trial.


Are you sure about this? In two prominent recent reported cases on that road, involving camera recording, there has been trial guilty plea conviction and significant sentence.

[G0ULI]

The emotiveness of an incident or claimed amnesia has no bearing on whether someone can be sent for trial. It is for the trial judge and/or jury to decide if a defendant is guilty of an offence. If a guilty verdict is delivered, then the judge may take into consideration all these factors before handing down a sentence. The law is rather dispassionate when it comes to dispensing justice for good reason.

Chronus suggests a horrific scenario that is so traumatic that few if any people could endure the consequences without blotting the incident from their brain. I would alternatively suggest that at 15° nose up and 225 knots, you will have no view of anything out the front except sky. Prior to that, you are too high and too far away to make out those sorts of details.

The AAIB report deals with the facts of the accident. The courts will deal with the facts of the accident. Any emotive issues will be considered only as they are relevant to the probable cause of the accident. So it is pointless speculating how, why, or if a case of amnesia might somehow absolve the pilot from the consequences of his actions that day. They won't as far as the law is concerned.

[eal401]

For example a lorry driver who wipes out yet another family on the A34 in Oxfordshire (which is becoming a regular occurrence now) simply claims amnesia of the event and we all say that fine you can go, no trial is necessary as we cannot try them.


Worked well for Harry Clarke in Glasgow. He claimed he couldn't remember anything before killing 6 people, admitted he'd lied about his medical history, not once but twice. He got away with it. Then, when he was caught driving when banned, he resigned from his post to dodge further punishment.

Given some posts here, there are a few here who would applaud him too....

[DaveReidUK]

Given some posts here, there are a few here who would applaud him too....

Ridiculous statement.

[Super VC-10]

Mods, time to close this thread methinks. Give the dead horse a decent funeral and stop flogging it. :ugh:

[airpolice]

I started this thread to discuss the report, not the crash.


I am concerned that the report makes so little of the failings of those tasked with regulation of the "airshow circus" and airworthiness in general.

[Mike Metcalf48]

IIRC from my Hunter flying back in the day, coarse aileron input at slow speed would cause departure from controlled flight. The resulting spin was quite unstable and thus dangerous outside of the test environment. We ensured pilots were aware of this trap and, if anybody would care to post it, is detailed as a warning in the pilots' notes. So I am not surprised this pilot was neither taught nor had practised recovery from slow speed inverted at the top of a loop (nb this wasn't a loop or even a 'bent loop' BTW). It would have been quite a leap of faith to do so when training in the Hunter. Once this pilot had found himself significantly below his gate (assuming he even was alert to the situation), he had little option. It is possible he could have avoided the ground if he'd flown optimum AOA - light buffet - but with the ground rushing up to him, the natural human reaction would be to pull harder.

I read the AAIB Hunter test report. The evaluated type was a single seat Hunter with an Avon 200. Whilst similar, it is quite a different beast to the 2-seat Avon 100 trainer. It doesn't matter how much you fudge it, it is not going to be representative and cannot be compared. The very capable TP should have known this and ensured a Hunter T7, in the same fit, weight and balance, was used to evaluate. So, I am afraid it is like apples and pears. The fact that the TP safely flew an 'escape manoeuvre' is down to his experience, ability - lots of Hunter time spent spinning, I am told - and pre-flight spin prevention planning on this distinctly different variant.

[n305fa]

Personally I think the 30 recommendations to the regulator regarding airworthiness and airshow regulation say quite a lot about the state of the air display regulation. The final recommendation to the DfT, for an independent review also says a lot

[airpolice]

But no real castigating of those who failed in their duty to protect the public?

I'm thinking of the pre-existing requirements that have not been observed. Why are we not reading of a "blame" for want of a better word, being laid at the door of those who thought it acceptable to not authenticate the adherence to rules?

[LOMCEVAK]

airpolice,

Look at the AAIB website and understand their remit; they do not apportion blame in any report about any aspect of an accident. Therefore, the Shoreham report is totally within their remit.

[Chronus]

Airpolice says he started this thread so that we discuss the report and not the crash. So I read the report again, for the umpteenth time. All I can make out is that it seems to be all about the crash. Am I missing something.

[n305fa]

But no real castigating of those who failed in their duty to protect the public?

I'm thinking of the pre-existing requirements that have not been observed. Why are we not reading of a "blame" for want of a better word, being laid at the door of those who thought it acceptable to not authenticate the adherence to rules?

For clarity here is the definition of the purpose of an AAIB investigation which is defined in law.

The Civil Aviation (Investigation of Air Accidents and Incidents) Regulations 1996 states

"Purpose of the investigation of accidents and incidents

4. The sole objective of the investigation of an accident or incident under these Regulations shall be the prevention of accidents and incidents. It shall not be the purpose of such an investigation to apportion blame or liability."

REGULATION (EU) No 996/2010 OF THE EUROPEAN PARLIAMENT AND OF THE COUNCIL of 20 October 2010 also states

(4) The sole objective of safety investigations should be the prevention of future accidents and incidents without apportioning blame or liability.

If you want blame and liability you've got the wrong organisation.

[terry holloway]

I started this thread to discuss the report, not the crash.


I am concerned that the report makes so little of the failings of those tasked with regulation of the "airshow circus" and airworthiness in general.
It's rather difficult to separate the two, and PPrune must be delighted that the thread is generating so much interest. It's a pity that so much of it is uninformed rubbish which will neither change the AAIB report nor persuade the CPS one way or the other. However at least Andy H now has a beauty parade of "experts" to help his defence.

[biscuit74]

I realise this thread has wandered from time to time into what I’d view as odd areas, which I’d rather not get into.
Can I bring up something which seems to me might be fairly central in all this?

Something which has puzzled me is that it is said that AH had not rehearsed the escape manoeuvre mentioned, to act as a get out if things look wrong partway through a ~looping manoeuvre. That seemed unusual, for an experienced aerobatic pilot originally from a military background, carrying out low level aerobatics in a fast jet.

Then I started to think about his ‘normal’ every day flying environment and at the associated psychology/mindset. Back in his RAF days, I presume AH would have been used to rehearsing and practicing manoeuvres many times, including all sorts of emergency situations. Quite normal military practice, since after all most of their flying is very realistic ‘practice’ against the possibility of a real threat situation.

However, for more than twenty years most of AH’s flying had been commercial flying I believe. In general in that environment, emergencies are only practiced in the simulator during scheduled refreshers and re-validation exercises. The routine day to day operation is oriented towards completion of the flight. Emergencies are briefed on and ‘rehearsed’ verbally or internally, they are not routinely flown, quite understandably.

Could this then have produced an inadvertent but entirely understandable mindset in which the routine expectation was to complete the planned exercises, with emergencies being discussed or internally reviewed only? Hence it would not have seemed necessary to actually trial that manoeuvre, which would make it much less likely to be used.
It seems quite possible to me – this is not to criticise, simply to try to understand. I can think of a few times in my life when I realised in hindsight I was applying inappropriate criteria to a judgment call, because I’d not got the correct mindset running, so to speak.

Could this be an area where more detailed oversight and formal pre-briefing etc. could help encourage detail rehearsal and possibly avert an incident?
I’d very much like to know what some of the experienced folk on here think.

[airpolice]

Biscuit74, I too have wondered about the escape move, and not having flown a Hunter I can't say that I have any real knowledge of how to do it, but I would expect that practice of that move would also involve reading the Pilot's Notes for the aircraft, and taking into account the situation at the apex, low, slow and out of energy... not a good time to roll the aircraft without being really sure of what's happening with the energy.


The aircraft is very spin resistant and is most reluctant to enter a spin unless coarse use is made of the rudder or ailerons during manoeuvres close to the stall, particularly in heavy buffet. Under these conditions, an erect spin is more likely to occur than an inverted spin, but the latter may result from coarse use of aileron, caused by, for example, a poorly executed loop, a stall turn type of manoeuvre or when full aileron rolling manoeuvres are performed and the control column is moved appreciably aft. It is recommended that theses pro spin conditions be avoided.

[mrangryofwarlingham]

MM and biscuit

My post #142 last section referred to this.

But that isn't the escape manoeuvre....it's accelerate whilst unloading....and roll level before you get to 45 degrees pitch. 1/2 Cuban or horizontal 8 depending on your upbringing....

[biscuit74]

Thanks mr angry, understood.
Either of the 'get outs' you mention - half roll off the top or unload & accelerate if far too slow etc., would work for me in my simple aeroplanes, and I have practiced them, being well used to my somewhat variable aerobatic ability! (In my case the unload and accelerate option would be more because a possible flick into an inverted spin would be more exciting than I'd like...)

It simply seemed unusual not to have practiced them in this came hence my speculation about mindset. I suppose cost or flying hours availability might be an issue, since the report seems to describe a very abbreviated conversion to type and to a Hunter aerobatic routine. If you don't think you need to trial any actual get out effort, this would not be a concern.

[LOMCEVAK]

airpolice,

taking into account the situation at the apex, low, slow and out of energy... not a good time to roll the aircraft without being really sure of what's happening with the energy

People use 'energy' far too liberally; here you mean airspeed. And at the apex of the accident manoeuvre the aircraft was not 'out of energy'; it had 105 KIAS and the data in Appendix H shows that with 80 KIAS it was possible and straightforward to execute an escape manoeuvre. However, if someone has not been trained to fly this and has not practised it then I fully accept that they may be very circumspect about trying it!

With respect to departures and spinning, I have only had two departures in a T7 and both because the handling pilot (not me!) allowed the rudder to float. One was during a full flap stall, and a 1 turn erect spin resulted, and the other was during a -1g full lateral stick roll, during which a developed spin did not occur. In both cases centralising the rudder and stick effected a recovery. The only inadvertent inverted spins that I have heard about were as a result of a centralised recovery from a nose high, low speed unusual position recovery, and I suspect that the rudder may well have floated due to sideslip in both cases.

mrangry..

In a 1/2 horizontal/Cuban 8 (rolling on a down 45 line), elevator and rudder are used to maintain a straight flightpath. In an escape manoeuvre, even on a down 45 line, in order to prevent a potential departure the rudder needs to be restrained at neutral and the elevator used to maintain close to the zero lift angle of attack (in practise neutral elevator/trim position). It is important that this subtle difference in control strategy is understood by anyone flying minimum speed loops at low level.

[LOMCEVAK]

biscuit74,

You are not alone in your opinion. On page 218 of the Shoreham report it states:

"Safety Recommendation 2017-002: It is recommended that the Civil Aviation Authority require pilots intending to conduct aerobatics at flying displays to be trained in performing relevant escape manoeuvres and require that their knowledge and ability to perform such manoeuvres should be assessed as part of the display authorisation process."

Hopefully, the next edition of CAP403 will include this.

[sika hulmuta]

Biscuit74,

A relevant question. Like AH I also have a military background and am presently employed in the airline business.

I also have wondered about this "escape manoeuvre" which he so say didn't practice.

I will give an example which many reading this may associate with. In the civilian world, every year (at least) we go into the simulator to practice an engine failure at V1 on takeoff, which is deemed a "worst case" by the regulatory authority. We get quite good at that over the years. However, as a simulator instructor conducting training as well as checking, I have also seen less predictable results if the engine failure occurs at a slightly different point. Say, 500ft IMC on departure. Every civilian pilot is proficient at V1 cuts, but I would also say at risk of significant error should the failure occur at a different point. Because it is rarely practiced.

The regulator can only dictate "worst case" proficiency. But is a failure at V1 actually "worst case" for checking? Should failures at different points be also mandatory? This is not a digression.

Similarly with the Shoreham accident. What is the escape manoeuvre he so say didn't practice? Is it at the top of the loop having not made the gates? (The V1 cut equivalent) Is it when pointing vertically downwards and realising all is not as anticipated? Is it at some other point? All equally relevant I suggest.

Putting my old military hat on as a low level pilot, there was always one thing and one thing only that was in the forefront of the mind. Dying of deceleration sickness. In those days, it was a not unusual occurrence. The ground is totally unforgiving, and no error is permitted when manoeuvring near the ground.

Not only could he have escaped from it easily at the top of the loop in several possible ways, without practicing some mythical "escape manoeuvre" to satisfy regulation, but he would have had that terrain awareness respect inbuilt which every low level fast jet pilot learns from the earliest of days. It becomes almost instinct to be extremely careful when pointing at the ground.

This is why I do not believe AH would have consciously flown the manoeuvre as it transpired. Something must have happened to explain WHY he continued.

[n305fa]

IIRC from my Hunter flying back in the day, coarse aileron input at slow speed would cause departure from controlled flight. The resulting spin was quite unstable and thus dangerous outside of the test environment. We ensured pilots were aware of this trap and, if anybody would care to post it, is detailed as a warning in the pilots' notes. So I am not surprised this pilot was neither taught nor had practised recovery from slow speed inverted at the top of a loop (nb this wasn't a loop or even a 'bent loop' BTW). It would have been quite a leap of faith to do so when training in the Hunter. Once this pilot had found himself significantly below his gate (assuming he even was alert to the situation), he had little option. It is possible he could have avoided the ground if he'd flown optimum AOA - light buffet - but with the ground rushing up to him, the natural human reaction would be to pull harder.

I read the AAIB Hunter test report. The evaluated type was a single seat Hunter with an Avon 200. Whilst similar, it is quite a different beast to the 2-seat Avon 100 trainer. It doesn't matter how much you fudge it, it is not going to be representative and cannot be compared. The very capable TP should have known this and ensured a Hunter T7, in the same fit, weight and balance, was used to evaluate. So, I am afraid it is like apples and pears. The fact that the TP safely flew an 'escape manoeuvre' is down to his experience, ability - lots of Hunter time spent spinning, I am told - and pre-flight spin prevention planning on this distinctly different variant.


Perhaps, given the technical findings (ejection seats etc) of the investigation, the TP couldn't find a civil reg T7 he was happy to operate.

Please correct me if Im wrong but I thought the thrust differences between the Avon 100 and the 200 Were compensated for by operating the 200 series engine rpm at 'reduced" rom based on RR data to simulate 100 series thrust during aeros

From my days at Boscombe flight test,when we had some T7s and F6's and FGA9s to play with, the wing, fin and horizontal stab/elevators Of the T7 and "big bore" single seaters were "aerodynamically" the same, there are differences in pylons etc. One of our F6's had one original wing and one "donated" from a T7 that had been reduced to spares.

The report states (can't remember where) that consideration was taken of the aerodynamic effect of the twin seat cockpit vs the single in the test aircraft.

While there may be performance differences i don't think it's anything like as severe as you suggest.

[DaveReidUK]

Perhaps, given the technical findings (ejection seats etc) of the investigation, the TP couldn't find a civil reg T7 he was happy to operate.

AFAIK, none of the other three T.7s on the UK register are currently flying.

[Basil]

OK, re the 'wrong type' mindset, I wasn't going to mention this because a) It's embarrassing and b) I have no idea if it's relevant - but:
Whilst current on a pretty powerful swept wing jet transport, I was doing a single engine piston renewal and, on the go-around, I started to increase the attitude inappropriately. Well, I don't know what kicked in first a) I was doing it wrong or b) the ASI was going the wrong way but I stuffed the nose down pretty quickly.
I can assure you that the controls/view/sounds/environment didn't look anything like a big jet - but (initially) I did it . . . .

[robdean]

My degree was in psychology, and from that perspective I feel few of the posited scenarios really allow for the vagaries of human cognition. The human mind takes the fewest shortcuts when deliberate undivided attention is being devoted to an unfamiliar task. This pilot was undertaking a somewhat familiar task, and thinking psychologically I'd speculate that something caused his attention to be distracted in a way which felt perfectly professional in the moment. Perhaps a thrust anomaly, perhaps a heading error. But immediately the new task is in the foreground. In such circumstances the 'routine' task can be done so 'automatically' that one may simply see what one expects to see, or not register something unexpected which is abnormal. Such 'misdirection' is the stock in trade of magicians, but is actually a fundamental weakness of human cognition.
My point is that nobody is immune to this: one can make it more or less likely, but it's always a potential occurrence. A lot of the debate about 'could a pilot overlook this or attempt that' misses the point: he was probably cognitively misdirected by something that was in itself relatively benign or even an objective or conjectured false alarm. A final tragic factor in such cases can be exacerbated confusion upon spotting the approaching danger: that anomaly may at least momentarily be attributed to the in-fact-trivial but unusual problem rather than the real one of being behind the overall situation.
The Invisible Gorilla: And Other Ways Our Intuitions Deceive Us (http://www.theinvisiblegorilla.com/gorilla_experiment.html)

[Capt Scribble]

Rolling out of a manoeuvre that has gone wrong hardly needs practicing. It is second nature to anyone who has flown aerobatics and those who have done a military QFI tour and taught UPs (unusual positions). The accident was caused because the pilot did not respect the gate parameters (for reasons unknown), or misjudged his ability to complete the manoeuvre.

[LOMCEVAK]

robdean,

Thank you for your post and that all sounds very familiar! The way you have written it appears to be related to a single distraction/misdirection followed by a single cognitive error. If you have a sequence of errors over a period of, say, 15 seconds (in this case incorrect pull-up airspeed, incorrect power setting, excessive roll angle change, continuing the manoeuvre when a decision criteria, the gate height, has been failed), is it still possible that all of these can be caused by a single distraction/misdirection before commencing a manoeuvre or is there a potential mechanism whereby each error constitutes the distraction that triggers the next error in the chain?

[robdean]

LOMCEVAK Misdirection may not be an ideal term, depending on how it is interpreted, in that an illusionist will actively misdirect, and the onlooker will be misdirected. Here there is no deliberate third-party misdirection, but the consequences can be the same.

People crash cars when texting not because they are deliberately not looking at the road: they think they are still monitoring the road. And to some extent they are, enough to usually have no consequences and thus leave the impression that their monitoring was unimpaired. Statistics prove this very wrong.

Texting is irresponsible, but problem solving in a cockpit can be essential. Yet if you focus on the wrong problem at the wrong moment, you may metaphorically be 'texting' whilst something catastrophic is developing. For instance, if in mid-manoeuvre you find yourself, say, surprised to be drifting compass bearing, or seeing a minor thrust anomaly, that need not be imminently dangerous. But the cognitive danger is: you fly a manoeuvre 50 times no problem. 51st time there's a trivial issue. You split attention to the very noticeable, unusual issue which you always otherwise devote in full to 'routine' monitoring which though routine and 'never' far from nominal is in fact safety critical. Then comes confusion and exponentiating attention-narrowing anxiety: you are behind the aircraft and something ugly is unfolding very fast. Probably because at some point you glanced and saw what you expected to see rather than what was really there.

This is perhaps an unrecognised area in that it is as much 'human limitation' as 'pilot error' - we must all constantly perform 'cognitive triage', devoting attention where is is most needed, but it is the nature of the human mind that it cannot get this right instantly on every occasion, especially as it takes some attention to even a trivial issue in order to simply establish that it is indeed trivial

A related danger lies in fixating upon an element of the anomaly which blinds you to the bigger problem, even to the extent of missing the obvious: I'd not be surprised for there to have been CFIT incidents involving crews busily trying to figure out why the stupid 'terrain' enunciation wouldn't shut up.

There is a psychological tenet which I could quote here outside its usual application: 'we are free to construe but bound by our constructions'. You can jump to any number of conclusions, but once you jump to one your mind is no longer open.

[Hebog]

AFAIK, none of the other three T.7s on the UK register are currently flying.


I believe there are two other T7's which were flying, until the ban - one of which did have an in date permit to fly certificate (expired May2016). Not sure on the 3rd as this is with a company that deals with military contracts and their aircraft are on the military register. However, it maybe because of the CAA grounding civilian hunters that those 2 couldn't be used. Has this been lifted does anyone know or is it still in place?


After all there is no real reason provided that all the maintenance is carried out correctly and the new guidelines meet etc that permit applications couldn't be considered - after all it would appear to be no heredity fault with the airframe itself. Aerobatics manoeuvres are still restricted for vintage jets and the Jet provosts have been displaying since without incident.

[RAT 5]

Let me speculate on the mindset, and the escape manoeuvre; and also on the day to day mind set and emergency practices.

Firstly, the commercial sim is used every 6 months to practice and check well known non-normal and emergency situations. Generally they are discussed, briefed and practiced; or they have been seen before and are a regular standards check. There are too many WTF moments.
There is speculation about the escape manoeuvre required during a loop and being low/slow at apex, and the knowledge & currency of that. If you were performing a straight forward simple loop along your line I would suspect you would be mindful of what to do in a coupe of 'what if' moments. The manoeuvre is a simple lop.
Now throw in the bent loop while making a line adjustment: where is the focus? I suggest it is on the line adjustment and not on the monitoring of the manoeuvre and the escape routes.
The low energy entry, both speed & height, and perhaps even too low a G pull-up. To be aware of all those and monitor the apex is quite a work load. Add in to that the line adjustment concentration and perhaps the monitoring of the 'gate' was lacking as the line adjustment took priority.
The root causes then become low energy at entry; wrong alignment at entry; wrong pull up point at entry. The last 2 could take over the prime concentration at apex as the required line for the descent becomes visible. Rolling away from that 'magnet' would be difficult human nature, and when, in the downward vertical, the realisation of the inevitable becomes apparent it is too late.

[n305fa]

I believe there are two other T7's which were flying, until the ban - one of which did have an in date permit to fly certificate (expired May2016). Not sure on the 3rd as this is with a company that deals with military contracts and their aircraft are on the military register. However, it maybe because of the CAA grounding civilian hunters that those 2 couldn't be used. Has this been lifted does anyone know or is it still in place?


After all there is no real reason provided that all the maintenance is carried out correctly and the new guidelines meet etc that permit applications couldn't be considered - after all it would appear to be no heredity fault with the airframe itself. Aerobatics manoeuvres are still restricted for vintage jets and the Jet provosts have been displaying since without incident.

Not sure if the Hunter grounding has been removed but there may be issues in compliance with MPD2016-01 http://publicapps.caa.co.uk/modalapplication.aspx?catid=1&pagetype=65&appid=11&mode=detail&id=7760

[scifi]

Whilst looking at the RPM plots in the AAIB Report, I find it strange that the RPM decreases so abruptly (twice) in the climb. If you extrapolate from 7000 to zero RPM, this would have taken about 6 seconds, whereas the extrapolated 'spool-ups' where in the normal region of 20+ seconds.


Maybe the graphs are not precisely drawn, but the rate of decrease of RPMs seems to indicate some sort of mechanical abnormality.

[G0ULI]

scifi

The engine speeds discussed and displayed around page 51 of the report were derived from audio recordings. The graphics show only a small portion of the vertical axis.

Elsewhere in the report it is claimed that a pilot would not be able to sense or hear any variation in the thrust level.

The data was arrived at through minute analysis of the audio recordings in an effort to explain why the aircraft did not achieve the target (gate) apex height and speed.

Historically there have been unexplained losses of thrust from similar engines while in military service but Rolls Royce, the manufacturer, have never been able to establish a definitive cause.

The engine was not spooling down towards zero, just a fall off of a few hundred rpm or so. This is enough to indicate that the thrust was not at maximum throughout the climb, or at any point in the climb. There appears to have been a reduction in thrust at two points in the climb. Rolls Royce have been unable to find any fault with the engine that may have resulted in less than full thrust being developed, nor for an intermittant reduction in thrust.

The alternative explanation offered is that the pilot did not initially select full thrust when commencing the climb and adjusted the throttle during the climb. There is no visual evidence from on board cameras to support this view and it would go against normal practice when performing this manoeuvre.

[Chuck Glider]

The root causes then become low energy at entry; wrong alignment at entry; wrong pull up point at entry. The last 2 could take over the prime concentration at apex as the required line for the descent becomes visible.
Interesting take on this, but it seems to me that the first two, low energy and wrong alignment at entry, would not be factors since surely these initiating parameters would be the most easily met, and they weren't.

[DaveReidUK]

The root causes then become low energy at entry; wrong alignment at entry; wrong pull up point at entry.

Given that impact with the ground resulted from divergence from the planned vertical profile of the manoeuvre, how does the aircraft's horizontal position or track become a "root cause" ?

[RAT 5]

Chuck: Indeed, they do not seem to have been met, as planned. Why? is a good question, as yet unanswered. I was considering the 'Why was the obvious escape manoeuvre not executed?' If the wrong alignment at pull up was realised on the run-in, and then the pull up point was changed to try and give more space; and then the plan to bend the loop was made on the way up (i.e. the manoeuvre was made 'on the fly' as it was being performed) and then the proper line was searched for going over the top. That is where the concentration would be and not on the gate parameters.
That's my thinking of a possible Why did he not roll out of the back side of the apex.

[falcon900]

Can we please not forget the dramatically reduced rpm after pull up?

[Hebog]

Could something mechanical have occurred that distracted him which wasn't picked up on the examination of the aircraft wreckage. After all it was very badly damaged in several areas and therefore could have masked a problem which the AAIB haven't noticed as they have presumed it was accident damage rather than pre-accident damage.


Could there have been an ASI or altimeter problem after all I didn't find any mention of them asking the other pilot, or AH if they had experienced any issues with the aircraft and if so, had they reported them verbally or in writing to the maintenance company.


I also note that the existing maintenance company queried with the CAA the maintenance of the aircraft from the previous company. Do they not get all the records(log books/maintenance records) when the aircraft is transferred from one company to another.

[Chuck Glider]

I doubt that is true Hebog, and if it were the case that some technical issue arose at the beginning of a low level aerobatic manouever then surely, without question, the only thing is to abandon the manouever.
We're not talking about some 'Galloping Ghost' type failure that blacked out the pilot.
Perhaps an on-the-ball FDD might have spotted it going wrong and called 'Display end' before the outcome became inevitable. Perhaps not.

So, from the information available to me:
Low entry height.
Low entry speed.
Less than full engine thrust on the up line.
The bending of the loop too early taking the Hunter off the vertical.
It seems to me that all of these factors contributed to AH not making that critical top gate, without which the default action should have been 'No-Go', not 'Go'. Regardless of anything else the one critical parameter he should have been actively looking for, and should have recognised that he had missed, was the top gate, height and speed, otherwise recover.

[H Peacock]

Hebog. In an endeavour to prevent a high-performance aircraft from trying to fly the second half of a loop without enough sky below it, you ensure that, before committing, you achieve your gate parameters. Make the gate - you've enough sky; don't make the gate - not enough sky. Really really simple, and black & white. Absolute basics to any display pilot.

A whole plethora of reasons why AH didn't make the gate - did they not find a mobile, perhaps he was texting! Of course he wasn't, but for whatever the reason on the way up he failed to make the gate, but that was not why he crashed. Approaching apex you have one job that shoots to the top of the queue. Ignore that job or worse, get it wrong, and the outcome is inevitable.

Mentioned before but perhaps akin to DH; land or GA. Lots of reasons why I may get distracted, but my job is to ensure that I don't and hence make the correct, timely, black/white call every time!

[G0ULI]

If something occured that affected the control of the aircraft or presented a distraction, the correct course of action would be to establish the aircraft in level flight and abandon the display. Misreading instruments in clear VMC flight should not be sufficient to cause an accident.

[RAT 5]

One wonders why the bent loop as a plan? A 90/180/270/360 roll on the way up is not uncommon, but this seemed to be a line adjustment made 'at the last minute'.
I know this is not an analysis directly related to the 'Why' of the crash, but to others with local display experience, is there a reason why the arrival was not along the axis and a simple loop made to open the display? I know the arrival track was from NE, but it would not be a long deviation to align with the axis from 5nm out. Are there restrictions?

[G0ULI]

The pilot's notes clearly show that this was a pre-planned manoeuvre. Although it is not specifically covered in the AAIB report, the bent loop seems to have been designed to maintain alignment as close as possible to the display line and avoid no fly and restricted areas around the airfield.

The intended exit track was only supposed to be 20° different from the entry. The actual exit track was at 60° variance from the entry track. The extra 40° of turn is unlikely to have directly contributed to the accident, but could be enough to disorientate a pilot when chosen markers and identifying points are not in the position they are expected to be.

The momentary confusion as the brain struggles to catch up and realign where you think you are, with where you actually are, would certainly be an unecessary distraction when other things are not going according to plan, such as low airspeed and not enough height to pull through a loop.

[Arfur Dent]

Agree with H Peacock.
Also, AH was not properly skilful or current to carry out a low level display in a Fast Jet on which he had a total of 40 - odd hours. The basic cause of this almost inevitable crash must be the sloppy CAA regulations that allowed him to have a Hunter Display Authority after demonstrating his skills on a completely different aircraft type.

[RAT 5]

Hunter Display Authority after demonstrating his skills on a completely different aircraft type.

Not necessarily a direct cause, perhaps contributory. But, even in the commercial aviation world an IR is type/class specific. i.e. an IR gained in an MPA jet is not valid for a single crew piston. Yet for a DA...................? Same organisation with very different rules & regs!!! Yet which is the more critical?

[terry holloway]

Agree with H Peacock.
Also, AH was not properly skilful or current to carry out a low level display in a Fast Jet on which he had a total of 40 - odd hours. The basic cause of this almost inevitable crash must be the sloppy CAA regulations that allowed him to have a Hunter Display Authority after demonstrating his skills on a completely different aircraft type.
That is hardly fair to the CAA, notwithstanding that they have tighneded their rules.
The cause is his failure to safely complete the planned manoeuvre. Other causes include the owner putting him in it in the first place despite his relative inexperience in Hunters.

[DaveReidUK]

The cause is his failure to safely complete the planned manoeuvre.

Or to safely abandon the planned manoeuvre.

[terry holloway]

Or to safely abandon the planned manoeuvre.
Quite!
One could also blame the organisers and the ADD! It always requires a chain of events!

[Arfur Dent]

You are both correct but as I've said many times before, AH would never have been allowed to display a Hunter with such low hours if he were still in the RAF. The CAA should have set specific rules ages ago with regard to currency and minimum experience requirements.

[RAT 5]

Arfur: I can think of cost, (but is that in CAA's remit?) but who at CAA would have the experience to start with a clean sheet of paper and devise suitable rules/regs for a DA? Surely, if they have no experience they should go to those that have and consult: i.e. ask RAF what their criteria are and consider. They might be slightly more lenient, but.... What are the RAF rules and by how much does the CAA differ? Would the RAF regs be workable in a civil role?

[9 lives]

AH would never have been allowed to display a Hunter with such low hours if he were still in the RAF. The CAA should have set specific rules ages ago with regard to currency and minimum experience requirements.

Though "display" does not require that the aircraft be intentionally flown inverted, or into "corner of the envelope" maneuvers. It seems to me at a distance, that probably AH would have been quite fine to gracefully display the Hunter, in a non demanding flight regime, and the audience would probably have been every bit as satisfied with the airshow.

As consumers of airshows, do the public need to see larger vintage aircraft flown through demanding aerobatics? Or could they be content with some graceful passes, if we the industry offered only that? Let the light, purpose build aerobatic aircraft provide those demanding displays, and allow the audience to enjoy the passive participation of the larger and vintage aircraft.

Though I have not read the report, I wonder if investigators consider the need for providing demanding aerobatic displays in larger vintage aircraft. Should the report ask, or should we (the pilots and "industry") ask ourselves: Are we offering too much to the public in these airshows?

[megan]

I think it's one of those things where no matter the requirements laid down accidents will happen. Even the best trained have come to grief. I think it was Hawker test pilot Bill Bedford who, during a demonstration flight in a Hunter in Switzerland, thought he was going to drill a hole in the pavement when on the back side of a loop. Forgot about field elevation, bit like the Thunderbird F-16 chap. Bill considered test and demonstration flying as the two most dangerous pass times in aviation.

[Arfur Dent]

Ratty
I think the current RAF rules state that a display pilot has to have a certain total number of hours on type and must have flown several more in the previous 14 days (someone did mention exact requirements in a previous post). Cost is obviously a huge factor but just because you can't afford to comply doesn't mean it's not necessary. Quoting several RAF accidents to current pilots only serves to emphasise the point. As the great Bill Bedford said - display flying is inherently dangerous. To attempt it with little or no experience and/or recency is asking for trouble.

[biscuit74]

Quoting Rat 5: "but who at CAA would have the experience to start with a clean sheet of paper and devise suitable rules/regs for a DA? Surely, if they have no experience they should go to those that have and consult... "

Absolutely. I'd have thought simple commonsense would say that allowing DA renewal on a vastly different, much simpler type was highly dubious for a start.
Allowing low level aerobatic displays to be carried out at all with so little evidence of pilot training and relevant currency on type seems remarkably laissez faire.

In fairness to the CAA I have to say it surprises me that AH was happy to display and aircraft in which he had had so little solid practice time. Possibly that is a function of his experience as an aerobatic pilot, or possibly it indicates there may have been a certain level of over-confidence. The old saw about old pilots and bold pilots perhaps?
A great shame that no other possible opportunities for anyone to break the chain of consequences were taken.

Step Turn - If I may say, I think you have made a very good point about the style of possible display. A less challenging display sequence would also have allowed AH to build currency and competence on type in a straightforward and useful way at low cost and risk all round.

[airpolice]

Though I have not read the report,

Jeez, really? Don't you think it might be relevant to this discussion?

Is it really a lot to ask?

That's not just thread drift, that's casting off and steaming away on a new course.

[2 sheds]

airpolice

Actually, Step Turn made a very valid point, which, if you stop to think about it instead of launching into an attack, does not require study of the report.

I often wonder what spectacle there is in a single small jet (and the Gnat was even smaller) performing vertical manoeuvres up to several thousand feet. Is it more for the pilots' pleasure/ego trip rather than the spectators'? Far more entertaining to see a pair of Stearmans at 500 ft.

[airpolice]

Biscuit74, you say you are surprised that he displayed it under the circumstances.

That's an important point right there. I suspect that too many "good eggs" are doing stuff they really shouldn't but nobody wants to call them out on it, due to multiple other things that they are apparently good at.

What we might be witnessing here is a combination of AH (and others) believing his own press, and also the CAA falling into the same trap, where they think they are policing the airshow business simply because they have some rules and nothing has gone wrong.

When it becomes unthinkable that your hero can't actually walk on water, you are not going to notice when things start to go bad.

[airpolice]

2Sheds, why don't you start a thread on air displays and what is and is not required to entertain people?

[configsafenot]

Many years ago a highly respected display pilot came incredibly close to disaster

He had a few of his aircraft sat on a taxiway and they were going to do a static photoshoot

One aircraft, a Sea Fury, was just a little bit out of shot

Quick as a flash the pilot jumped into the cockpit, had the engine running almost at full tilt and spun the plane on its axis and into the right position for the shot

That could have gotten him into all sorts of issues...not least had there been anyone close to the Fury at the time....he did not shout "stand clear" or anything, he just got in there, started her up and spun the thing on its wheels without a second thought

Complacency breeds contempt

The pilot of the Hunter at Shoreham maybe of a similar mindset, the "I can do this with my eyes closed" type

Display flying is inherently dangerous even at the most well organised shows...God knows I have lost a few friends over the years at well organised dispalys and air races to know that sometimes you can be a little too relaxed, maybe stretch your ability way beyond your capability....and sometimes the adrenalin from "giving the paying crowd something special" can cloud the judgement in even the most experienced pilot

Complacency of "I can do that" turns into the contempt of "I can do that BETTER"

Shoreham by virtue of its location is a tough airfield for displaying, its not the most open or the least built up...major roads, housing etc, so its always been a tough call performing there, afterall even the Red Arrows cringe at the thought

You can add legislation and safety advice and rules til one is blue in the face but when you have a falible human being at the end of the line sitting in the cockpit and who by nature of the beast can get a little carried away with what they are doing cos "I can do this" complacency, then tragedy will almost always strike eventually

Shoreham Airshow will always be difficult, as are many airshows for a variety of reasons and the powers at be can legislate and throw rules at airshows til the cows come home but its not going to prevent accidents completely...not when you have a human being at the controls ultimately in charge of his or her plane

Personally I hope that airshows continue for decades to come, yes there will be more deaths and injuries but you can say that about every single thing in life and you cannot ever make anything 100% safe

The old chestnut about lessons being learnt...yes there are many from Shoreham to take on board and for pilots and organisers to try and prevent another tragedy

Can they ever make airshows 100% safe.....no, its impossible

Is that reason enough to stop performing at airshows...absolutely not

Just as every carcrash does not stop everyone from driving a car

You can do as much as possible to prevent another Shoreham but complacency will always be there lurking to catch out a pilot who feels "I can do this BETTER" and when they try, they crash & burn

Its not legislation or safety rules needed....its basic complacency that has no place in the cockpit

[9 lives]

Jeez, really? Don't you think it might be relevant to this discussion?

Is it really a lot to ask?

That's not just thread drift, that's casting off and steaming away on a new course.

Yeah, it's a lot to ask. I've read a few excerpts, though I allow that there may be information in there relevant to what I wrote, of which I am unaware.

In any case, I doubt that the AAIB has extended itself to the point of commenting on the "consumer expectation" aspect of airshows, as a causal factor. Spectators will watch what we an industry will offer. Add "death defying" to the ads, and they want more. The spectators will not ever say to the industry: "Hey, don't take so much risk, we're happy with graceful flybys.". They're not that knowledgeable, nor disciplined. We, the industry, must discipline ourselves, or risk adverse regulators will do it for us.

I doubt a report will explore this aspect of air display, perhaps its beyond the mandate of the AAIB. Airshow pilots are eager to satisfy the spectator expectation of an exciting display, within easy view - (low). Perhaps pilots are too eager to please sometimes, but they could be trying to please to unrealistic expectations.

[G0ULI]

The unique aspect of this incident is that it was not the spectators that got killed or injured, but uninvolved members of the public away from the display area. That is what has sparked public concern and an enquiry into why the regulations designed to prevent such accidents failed so spectacularly.

[Super VC-10]

At least two of those killed were there specifically to spectate. For the sake of saving a few quid they paid with their lives.

[G0ULI]

Super VC-10
It might also be argued that they decided to spectate from that location because it was away from the danger of the officially designated display area. A circular discussion that in no way mitigates the failings of the regulations that were supposed to protect the public at large.

[Tay Cough]

Surely then it's also worth arguing that the "officially designated display area" includes the official crowd line and sterile area behind that which is nominally "not dangerous" - as the rules have seemingly ensured since the DH110 accident. Hence previous discussion about "naughty fields" at various venues.

[Chronus]

At least two of those killed were there specifically to spectate. For the sake of saving a few quid they paid with their lives.

How can you be so certain and be so unkind both at the same time. You might as well have said those who lost their lives on Westminster Bridge in equal tragic circumstances so recently,must have been cheap skates crossing the bridge on foot and not in a taxi or bus. I must say I find the comment offensive to say the least.

[RAT 5]

Is Shoreham suitable for a beach display?